diff --git a/app/models/file_yard.rb b/app/models/file_yard.rb
index ef18b2ce..79e8f04d 100644
--- a/app/models/file_yard.rb
+++ b/app/models/file_yard.rb
@@ -16,9 +16,12 @@ class FileYard
     sanitize_file_name(name)
     if io.kind_of?(Tempfile)
       io.close
+      check_upload_size(io.size)
       FileUtils.mv(io.path, file_path(name))
     else
-      File.open(file_path(name), 'wb') { |f| f.write(io.read) }
+      content = io.read
+      check_upload_size(content.length)
+      File.open(file_path(name), 'wb') { |f| f.write(content) }
     end
     # just in case, restrict read access and prohibit write access to the uploaded file
     FileUtils.chmod(0440, file_path(name))
@@ -44,5 +47,12 @@ class FileYard
             "Only latin characters, digits, dots, underscores and dashes are accepted.")
     end
   end
+  
+  def check_upload_size(actual_upload_size)
+    if actual_upload_size > @max_upload_size.kilobytes
+      raise Instiki::ValidationError.new("Uploaded file size (#{actual_upload_size / 1024} " + 
+              "kbytes) exceeds the maximum (#{@max_upload_size} kbytes) set for this wiki")
+    end
+  end
 
 end
diff --git a/test/unit/file_yard_test.rb b/test/unit/file_yard_test.rb
index 6598caa1..ece421ff 100755
--- a/test/unit/file_yard_test.rb
+++ b/test/unit/file_yard_test.rb
@@ -13,6 +13,11 @@ class FileYardTest < Test::Unit::TestCase
     @yard = FileYard.new(file_path, 100)
   end
 
+  def test_check_upload_size
+    assert_nothing_raised { @yard.check_upload_size(100.kilobytes) }
+    assert_raises(Instiki::ValidationError) { @yard.check_upload_size(100.kilobytes + 1) }
+  end
+
   def test_files
     assert_equal [], @yard.files
     
@@ -28,6 +33,32 @@ class FileYardTest < Test::Unit::TestCase
     assert_equal "#{file_path}/abcd", @yard.file_path('abcd')
   end
 
+  def test_size_limit
+    @yard = FileYard.new(file_path, 1)
+    one_kylobyte_string = "a" * 1024
+
+    # as StringIO
+    assert_nothing_raised { 
+      @yard.upload_file('acceptable_file', StringIO.new(one_kylobyte_string)) 
+    }
+    assert_raises(Instiki::ValidationError) { 
+      @yard.upload_file('one_byte_too_long', StringIO.new(one_kylobyte_string + 'a')) 
+    }
+
+    # as Tempfile
+    require 'tempfile'
+    Tempfile.open('acceptable_file') { |f| f.write(one_kylobyte_string) } 
+      assert_nothing_raised { 
+        @yard.upload_file('acceptable_file', f) 
+      }
+    }
+    Tempfile.open('one_byte_too_long') { |f| f.write(one_kylobyte_string + 'a')
+      assert_nothing_raised { 
+        @yard.upload_file('one_byte_too_long_2', f)
+      }
+    }
+  end
+
   def file_path
     "#{RAILS_ROOT}/storage/test/instiki"
   end