diff --git a/app/controllers/finance/invoices_controller.rb b/app/controllers/finance/invoices_controller.rb
index a38328db..a21d2f96 100644
--- a/app/controllers/finance/invoices_controller.rb
+++ b/app/controllers/finance/invoices_controller.rb
@@ -1,7 +1,7 @@
 class Finance::InvoicesController < ApplicationController
 
   def index
-    @invoices = Invoice.includes(:supplier, :delivery, :order).order('date DESC').page(params[:page]).per(@per_page)
+    @invoices = Invoice.includes(:supplier, :deliveries, :orders).order('date DESC').page(params[:page]).per(@per_page)
   end
 
   def show
@@ -9,9 +9,9 @@ class Finance::InvoicesController < ApplicationController
   end
 
   def new
-    @invoice = Invoice.new :supplier_id => params[:supplier_id],
-                           :delivery_id => params[:delivery_id],
-                           :order_id => params[:order_id]
+    @invoice = Invoice.new :supplier_id => params[:supplier_id]
+    @invoice.deliveries << Delivery.find_by_id(params[:delivery_id]) if params[:delivery_id]
+    @invoice.orders << Order.find_by_id(params[:order_id]) if params[:order_id]
   end
 
   def edit
@@ -24,9 +24,9 @@ class Finance::InvoicesController < ApplicationController
 
     if @invoice.save
       flash[:notice] = I18n.t('finance.create.notice')
-      if @invoice.order
+      if @invoice.orders.count == 1
         # Redirect to balancing page
-        redirect_to new_finance_order_url(order_id: @invoice.order.id)
+        redirect_to new_finance_order_url(order_id: @invoice.orders.first.id)
       else
         redirect_to [:finance, @invoice]
       end
diff --git a/app/models/delivery.rb b/app/models/delivery.rb
index 0ef7b62d..367cdc1f 100644
--- a/app/models/delivery.rb
+++ b/app/models/delivery.rb
@@ -1,7 +1,7 @@
 class Delivery < ActiveRecord::Base
 
   belongs_to :supplier
-  has_one :invoice
+  belongs_to :invoice
   has_many :stock_changes, -> { includes(:stock_article).order('articles.name ASC') }, :dependent => :destroy
 
   scope :recent, -> { order('created_at DESC').limit(10) }
diff --git a/app/models/invoice.rb b/app/models/invoice.rb
index fa8c1a1a..0491e153 100644
--- a/app/models/invoice.rb
+++ b/app/models/invoice.rb
@@ -1,9 +1,9 @@
 class Invoice < ActiveRecord::Base
 
   belongs_to :supplier
-  belongs_to :delivery
-  belongs_to :order
   belongs_to :created_by, :class_name => 'User', :foreign_key => 'created_by_user_id'
+  has_many :deliveries
+  has_many :orders
 
   validates_presence_of :supplier_id
   validates_numericality_of :amount, :deposit, :deposit_credit
diff --git a/app/models/order.rb b/app/models/order.rb
index ff2dbf38..4ad020dd 100644
--- a/app/models/order.rb
+++ b/app/models/order.rb
@@ -9,9 +9,9 @@ class Order < ActiveRecord::Base
   has_many :group_orders, :dependent => :destroy
   has_many :ordergroups, :through => :group_orders
   has_many :users_ordered, :through => :ordergroups, :source => :users
-  has_one :invoice
   has_many :comments, -> { order('created_at') }, :class_name => "OrderComment"
   has_many :stock_changes
+  belongs_to :invoice
   belongs_to :supplier
   belongs_to :updated_by, :class_name => 'User', :foreign_key => 'updated_by_user_id'
   belongs_to :created_by, :class_name => 'User', :foreign_key => 'created_by_user_id'
diff --git a/app/views/finance/invoices/_form.html.haml b/app/views/finance/invoices/_form.html.haml
index 7777d92a..2b305756 100644
--- a/app/views/finance/invoices/_form.html.haml
+++ b/app/views/finance/invoices/_form.html.haml
@@ -1,11 +1,11 @@
 = simple_form_for([:finance, @invoice]) do |f|
-  = f.hidden_field :delivery_id
-  = f.hidden_field :order_id
+  = f.association :deliveries, multiple: true, as: :hidden
+  = f.association :orders, multiple: true, as: :hidden
 
-  - if @invoice.delivery
-    %p= t('finance.invoices.linked', what_link: link_to(t('finance.invoices.linked_delivery'), [@invoice.supplier,@invoice.delivery])).html_safe
-  - if @invoice.order
-    %p= t('finance.invoices.linked', what_link: link_to(t('finance.invoices.linked_order'), new_finance_order_path(order_id: @invoice.order.id))).html_safe
+  - if @invoice.deliveries.first
+    %p= t('finance.invoices.linked', what_link: link_to(t('finance.invoices.linked_delivery'), [@invoice.supplier,@invoice.deliveries.first])).html_safe
+  - if @invoice.orders.first
+    %p= t('finance.invoices.linked', what_link: link_to(t('finance.invoices.linked_order'), new_finance_order_path(order_id: @invoice.orders.first.id))).html_safe
 
   - if @invoice.created_at
     = f.input :created_at do
diff --git a/app/views/finance/invoices/_invoices.html.haml b/app/views/finance/invoices/_invoices.html.haml
index c701bdab..830eb0e2 100644
--- a/app/views/finance/invoices/_invoices.html.haml
+++ b/app/views/finance/invoices/_invoices.html.haml
@@ -10,8 +10,8 @@
       %th= heading_helper Invoice, :date
       %th= heading_helper Invoice, :paid_on
       %th= heading_helper Invoice, :amount
-      %th= heading_helper Invoice, :delivery
-      %th= heading_helper Invoice, :order
+      %th= heading_helper Invoice, :deliveries
+      %th= heading_helper Invoice, :orders
       %th= heading_helper Invoice, :note
       %th
       %th
@@ -23,8 +23,14 @@
         %td= link_to h(format_date invoice.date), finance_invoice_path(invoice)
         %td= format_date invoice.paid_on
         %td= number_to_currency invoice.amount
-        %td= link_to Delivery.model_name.human, [invoice.supplier,invoice.delivery] if invoice.delivery
-        %td= link_to format_date(invoice.order.ends), new_finance_order_path(order_id: invoice.order_id) if invoice.order
+        %td><
+          - invoice.deliveries.each_with_index do |delivery, index|
+            = ', ' if index > 0
+            = link_to format_date(delivery.delivered_on), [delivery.supplier,delivery]
+        %td><
+          - invoice.orders.each_with_index do |order, index|
+            = ', ' if index > 0
+            = link_to format_date(order.ends), new_finance_order_path(order_id: order)
         %td= truncate(invoice.note)
         %td= link_to t('ui.edit'), edit_finance_invoice_path(invoice), class: 'btn btn-mini'
         %td= link_to t('ui.delete'), finance_invoice_path(invoice), :data => {:confirm => t('.confirm_delete')}, :method => :delete,
diff --git a/app/views/finance/invoices/show.html.haml b/app/views/finance/invoices/show.html.haml
index 97034a04..748de7f4 100644
--- a/app/views/finance/invoices/show.html.haml
+++ b/app/views/finance/invoices/show.html.haml
@@ -10,14 +10,20 @@
   %b= heading_helper(Invoice, :supplier) + ':'
   = @invoice.supplier.name
 
-- if @invoice.delivery
+- if @invoice.deliveries.count > 0
   %p
-    %b= heading_helper(Invoice, :delivery) + ':'
-    = t('finance.invoices.linked', what_link: link_to(t('finance.invoices.linked_delivery'), [@invoice.supplier,@invoice.delivery])).html_safe
-- if @invoice.order
+    %b= heading_helper(Invoice, :deliveries) + ':'
+    %span><
+      - @invoice.deliveries.order(:delivered_on).each_with_index do |delivery, index|
+        = ', ' if index > 0
+        = link_to format_date(delivery.delivered_on), [delivery.supplier,delivery]
+- if @invoice.orders.count > 0
   %p
-    %b= heading_helper(Invoice, :order) + ':'
-    = t('finance.invoices.linked', what_link: link_to(t('finance.invoices.linked_order'), @invoice.order)).html_safe
+    %b= heading_helper(Invoice, :orders) + ':'
+    %span><
+      - @invoice.orders.order(:ends).each_with_index do |order, index|
+        = ', ' if index > 0
+        = link_to format_date(order.ends), new_finance_order_path(order_id: order)
 
 %p
   %b= heading_helper(Invoice, :number) + ':'
diff --git a/config/locales/de.yml b/config/locales/de.yml
index 0b8661a5..8950c7ff 100644
--- a/config/locales/de.yml
+++ b/config/locales/de.yml
@@ -57,12 +57,12 @@ de:
         created_at: Erstellt am
         created_by: Erstellt von
         date: Rechnungsdatum
-        delivery: Lieferung
+        deliveries: Lieferung
         deposit: Pfand berechnet
         deposit_credit: Pfand gutgeschrieben
         note: Notiz
         number: Nummer
-        order: Bestellung
+        orders: Bestellung
         paid_on: Bezahlt am
         supplier: Lieferant
       message:
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 46855dc2..3ddc80b9 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -57,12 +57,12 @@ en:
         created_at: Created at
         created_by: Created by
         date: Billing date
-        delivery: Delivery
+        deliveries: Delivery
         deposit: Deposit charged
         deposit_credit: Deposit returned
         note: Note
         number: Number
-        order: Order
+        orders: Order
         paid_on: Paid on
         supplier: Supplier
       message:
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index a214ad9a..fc31d566 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -57,12 +57,12 @@ fr:
         created_at: Créé le
         created_by: "Établi par"
         date: Date de facturation
-        delivery: Réapprovisionnement
+        deliveries: Réapprovisionnement
         deposit: Consigne facturée
         deposit_credit: Consigne remboursée
         note: Note
         number: Numéro
-        order: Commande
+        orders: Commande
         paid_on: Payée le
         supplier: Fournisseur-e
       message:
diff --git a/config/locales/nl.yml b/config/locales/nl.yml
index 304fdbb9..f10f1546 100644
--- a/config/locales/nl.yml
+++ b/config/locales/nl.yml
@@ -57,12 +57,12 @@ nl:
         created_at: Gemaakt op
         created_by: Gemaakt door
         date: Factuurdatum
-        delivery: Levering
+        deliveries: Levering
         deposit: Statiegeld in rekening gebracht
         deposit_credit: Statiegeld teruggekregen
         note: Notitie
         number: Nummer
-        order: Bestelling
+        orders: Bestelling
         paid_on: Betaald op
         supplier: Leverancier
       message:
diff --git a/db/migrate/20160217134742_change_invoice_relation.rb b/db/migrate/20160217134742_change_invoice_relation.rb
new file mode 100644
index 00000000..55c3ad98
--- /dev/null
+++ b/db/migrate/20160217134742_change_invoice_relation.rb
@@ -0,0 +1,21 @@
+class ChangeInvoiceRelation < ActiveRecord::Migration
+  def up
+    add_column :deliveries, :invoice_id, :integer
+    execute 'UPDATE deliveries SET invoice_id = (SELECT id FROM invoices WHERE delivery_id = deliveries.id)'
+    remove_column :invoices, :delivery_id
+
+    add_column :orders, :invoice_id, :integer
+    execute 'UPDATE orders SET invoice_id = (SELECT id FROM invoices WHERE order_id = orders.id)'
+    remove_column :invoices, :order_id
+  end
+
+  def down
+    add_column :invoices, :delivery_id
+    execute 'UPDATE invoices SET delivery_id = (SELECT id FROM deliveries WHERE invoice_id = invoices.id)'
+    remove_column :deliveries, :invoice_id, :integer
+
+    add_column :invoices, :order_id
+    execute 'UPDATE invoices SET order_id = (SELECT id FROM orders WHERE invoice_id = invoices.id)'
+    remove_column :orders, :invoice_id, :integer
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index ac1d804c..edffedda 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20160217124256) do
+ActiveRecord::Schema.define(version: 20160217134742) do
 
   create_table "article_categories", force: :cascade do |t|
     t.string "name",        limit: 255, default: "", null: false
@@ -71,6 +71,7 @@ ActiveRecord::Schema.define(version: 20160217124256) do
     t.date     "delivered_on"
     t.datetime "created_at"
     t.text     "note",         limit: 65535
+    t.integer  "invoice_id"
   end
 
   add_index "deliveries", ["supplier_id"], name: "index_deliveries_on_supplier_id", using: :btree
@@ -155,8 +156,6 @@ ActiveRecord::Schema.define(version: 20160217124256) do
 
   create_table "invoices", force: :cascade do |t|
     t.integer  "supplier_id",    limit: 4
-    t.integer  "delivery_id",    limit: 4
-    t.integer  "order_id",       limit: 4
     t.string   "number",         limit: 255
     t.date     "date"
     t.date     "paid_on"
@@ -169,7 +168,6 @@ ActiveRecord::Schema.define(version: 20160217124256) do
     t.integer  "created_by_user_id"
   end
 
-  add_index "invoices", ["delivery_id"], name: "index_invoices_on_delivery_id", using: :btree
   add_index "invoices", ["supplier_id"], name: "index_invoices_on_supplier_id", using: :btree
 
   create_table "memberships", force: :cascade do |t|
@@ -226,6 +224,7 @@ ActiveRecord::Schema.define(version: 20160217124256) do
     t.decimal  "foodcoop_result",                  precision: 8, scale: 2
     t.integer  "created_by_user_id", limit: 4
     t.datetime "boxfill"
+    t.integer  "invoice_id"
   end
 
   add_index "orders", ["state"], name: "index_orders_on_state", using: :btree