diff --git a/features/seed_once.feature b/features/seed_once.feature
new file mode 100644
index 0000000..42a00c9
--- /dev/null
+++ b/features/seed_once.feature
@@ -0,0 +1,5 @@
+Feature: Seed Once
+  Scenario: Seed a record once
+    Given I have already seeded a record
+    When I seed the record using seed_once
+    Then I should not seed the record again
diff --git a/features/step_definitions/given/i_have_already_seeded_a_record.rb b/features/step_definitions/given/i_have_already_seeded_a_record.rb
new file mode 100644
index 0000000..3626d56
--- /dev/null
+++ b/features/step_definitions/given/i_have_already_seeded_a_record.rb
@@ -0,0 +1,6 @@
+Given(/^I have already seeded a record$/) do
+  record = Record.new
+  record[:_id] = 1
+  record[:data] = 'existing'
+  record.upsert
+end
diff --git a/features/step_definitions/then/i_should_not_seed_the_record_again.rb b/features/step_definitions/then/i_should_not_seed_the_record_again.rb
new file mode 100644
index 0000000..153e8a3
--- /dev/null
+++ b/features/step_definitions/then/i_should_not_seed_the_record_again.rb
@@ -0,0 +1,4 @@
+Then(/^I should not seed the record again$/) do
+  Record.count.should == 1
+  Record.find(1).data.should == 'existing'
+end
diff --git a/features/step_definitions/when/i_seed_the_record_using_seed_once.rb b/features/step_definitions/when/i_seed_the_record_using_seed_once.rb
new file mode 100644
index 0000000..880550d
--- /dev/null
+++ b/features/step_definitions/when/i_seed_the_record_using_seed_once.rb
@@ -0,0 +1,6 @@
+When(/^I seed the record using seed_once$/) do
+  Record.seed_once :id do |s|
+    s.id = 1
+    s.data = 'data'
+  end
+end
diff --git a/lib/seed-fu-mongoid.rb b/lib/seed-fu-mongoid.rb
index ae751eb..4e86b4d 100644
--- a/lib/seed-fu-mongoid.rb
+++ b/lib/seed-fu-mongoid.rb
@@ -27,12 +27,8 @@ end
 
 module Mongoid::Document
   module ClassMethods
-    def seed_once(*constraints)
-      seeder = SeedFuMongoid::DocumentSeeder.new(self, constraints, block)
-
-      if seeder.new?
-        seeder.seed!
-      end
+    def seed_once(*constraints, &block)
+      SeedFuMongoid::DocumentSeeder.new(self, constraints, block).seed_once!
     end
 
     def seed(*constraints_and_objects, &block)
diff --git a/lib/seed-fu-mongoid/document_seeder.rb b/lib/seed-fu-mongoid/document_seeder.rb
index 941cd8c..5b9b663 100644
--- a/lib/seed-fu-mongoid/document_seeder.rb
+++ b/lib/seed-fu-mongoid/document_seeder.rb
@@ -58,9 +58,9 @@ module SeedFuMongoid
         return @constraint_search if @constraint_search
 
         @constraint_search = {}
-        constraints.each do |constraint|
+        @constraints.each do |constraint|
           if data[constraint]
-            @constraint_search[constraint] = proxy[constraint]
+            @constraint_search[constraint] = data[constraint]
           else
             raise ConstraintNotDefined.new(constraint)
           end
@@ -78,6 +78,10 @@ module SeedFuMongoid
 
         document.upsert
       end
+
+      def new?
+        !document.persisted?
+      end
     end
 
     def create_document(block_or_object)
@@ -94,9 +98,20 @@ module SeedFuMongoid
       end
     end
 
-    def new?
-      !document.persisted?
+    def seed_once!
+      if @objects.empty?
+        document = create_document(@block)
+        if document.new?
+          document.seed!
+        end
+      else
+        @objects.each do |object|
+          document = create_document(object)
+          if document.new?
+            document.seed!
+          end
+        end
+      end
     end
   end
 end
-