diff --git a/app/controllers/imports_controller.rb b/app/controllers/imports_controller.rb
index 79a5ced..ffe7f75 100644
--- a/app/controllers/imports_controller.rb
+++ b/app/controllers/imports_controller.rb
@@ -63,6 +63,19 @@ class ImportsController < ApplicationController
     @attributes = issue.safe_attribute_names
     @custom_fields = issue.editable_custom_field_values.map(&:custom_field)
 
+    if @import.mapping.empty?
+      @import.settings['mapping'] = {}
+      # Core issue fields
+      %w(subject description priority category assigned_to fixed_version is_private parent_issue_id start_date due_date estimated_hours done_ratio).each do |field|
+        label = l("field_#{field.gsub(/\_id$/, '')}".to_sym)
+        @import.mapping[field] = @import.headers.index(label)
+      end
+      # Custom fields
+      issue.available_custom_fields.each do |field|
+        @import.mapping["cf_#{field.id}"] = @import.headers.index(field.name)
+      end
+    end
+
     if request.post?
       respond_to do |format|
         format.html {
@@ -121,4 +134,5 @@ class ImportsController < ApplicationController
   def max_items_per_request
     5
   end
+
 end