diff --git a/python/ycm/tests/vimsupport_test.py b/python/ycm/tests/vimsupport_test.py
index d7a7d468..b4367f8b 100644
--- a/python/ycm/tests/vimsupport_test.py
+++ b/python/ycm/tests/vimsupport_test.py
@@ -1537,28 +1537,41 @@ def SelectFromList_Negative_test( vim_eval ):
 @patch( 'ycm.vimsupport.SearchInCurrentBuffer', return_value = 0 )
 @patch( 'vim.current' )
 def InsertNamespace_insert_test( vim_current, *args ):
-  contents = [ 'var taco = Math' ]
+  contents = [ '',
+               'namespace Taqueria {',
+               '',
+               '  int taco = Math' ]
   vim_current.buffer = VimBuffer( '', contents = contents )
 
   vimsupport.InsertNamespace( 'System' )
 
   expected_buffer = [ 'using System;',
-                      'var taco = Math' ]
+                      '',
+                      'namespace Taqueria {',
+                      '',
+                      '  int taco = Math' ]
   AssertBuffersAreEqualAsBytes( expected_buffer, vim_current.buffer )
 
 
 @patch( 'ycm.vimsupport.VariableExists', return_value = False )
-@patch( 'ycm.vimsupport.SearchInCurrentBuffer', return_value = 1 )
+@patch( 'ycm.vimsupport.SearchInCurrentBuffer', return_value = 2 )
 @patch( 'vim.current' )
 def InsertNamespace_append_test( vim_current, *args ):
-  contents = [ 'using System;', '', 'var taco;', 'var salad = new List']
+  contents = [ 'namespace Taqueria {',
+               '  using System;',
+               '',
+               '  class Tasty {',
+               '    int taco;',
+               '    List salad = new List']
   vim_current.buffer = VimBuffer( '', contents = contents )
 
   vimsupport.InsertNamespace( 'System.Collections' )
 
-  expected_buffer = [ 'using System;',
-                      'using System.Collections;',
+  expected_buffer = [ 'namespace Taqueria {',
+                      '  using System;',
+                      '  using System.Collections;',
                       '',
-                      'var taco;',
-                      'var salad = new List' ]
+                      '  class Tasty {',
+                      '    int taco;',
+                      '    List salad = new List']
   AssertBuffersAreEqualAsBytes( expected_buffer, vim_current.buffer )
diff --git a/python/ycm/vimsupport.py b/python/ycm/vimsupport.py
index 650ad1b3..30f9a452 100644
--- a/python/ycm/vimsupport.py
+++ b/python/ycm/vimsupport.py
@@ -846,9 +846,11 @@ def InsertNamespace( namespace ):
       return
 
   pattern = '^\s*using\(\s\+[a-zA-Z0-9]\+\s\+=\)\?\s\+[a-zA-Z0-9.]\+\s*;\s*'
+  existing_indent = ''
   line = SearchInCurrentBuffer( pattern )
-  existing_line = LineTextInCurrentBuffer( line )
-  existing_indent = re.sub( r"\S.*", "", existing_line )
+  if line > 0:
+    existing_line = LineTextInCurrentBuffer( line )
+    existing_indent = re.sub( r"\S.*", "", existing_line )
   new_line = "{0}using {1};\n\n".format( existing_indent, namespace )
   replace_pos = { 'line_num': line + 1, 'column_num': 1 }
   ReplaceChunk( replace_pos, replace_pos, new_line, 0, 0, vim.current.buffer )
@@ -856,11 +858,14 @@ def InsertNamespace( namespace ):
 
 
 def SearchInCurrentBuffer( pattern ):
+  """ Returns the 1-indexed line on which the pattern matches
+  (going UP from the current position) or 0 if not found """
   return GetIntValue( "search('{0}', 'Wcnb')".format( EscapeForVim( pattern )))
 
 
 def LineTextInCurrentBuffer( line ):
-  return vim.current.buffer[ line ]
+  """ Returns the text on the 1-indexed line (NOT 0-indexed) """
+  return vim.current.buffer[ line - 1 ]
 
 
 def ClosePreviewWindow():