diff --git a/src/app/range.coffee b/src/app/range.coffee
index 11efe0c94..3464a3bce 100644
--- a/src/app/range.coffee
+++ b/src/app/range.coffee
@@ -11,6 +11,11 @@ class Range
     else
       new Range(object.start, object.end)
 
+  @fromPointWithDelta: (point, rowDelta, columnDelta) ->
+    pointA = Point.fromObject(point)
+    pointB = new Point(point.row + rowDelta, point.column + columnDelta)
+    new Range(pointA, pointB)
+
   constructor: (pointA = new Point(0, 0), pointB = new Point(0, 0)) ->
     pointA = Point.fromObject(pointA)
     pointB = Point.fromObject(pointB)
diff --git a/src/packages/autocomplete/spec/autocomplete-spec.coffee b/src/packages/autocomplete/spec/autocomplete-spec.coffee
index c9a22d507..8190f3d31 100644
--- a/src/packages/autocomplete/spec/autocomplete-spec.coffee
+++ b/src/packages/autocomplete/spec/autocomplete-spec.coffee
@@ -96,6 +96,15 @@ describe "Autocomplete", ->
         expect(autocomplete.matchesList.find('li').length).toBe 1
         expect(autocomplete.matchesList.find('li:eq(0)')).toHaveText "No matches found"
 
+      it "autocompletes word and replaces case of prefix with case of word", ->
+        editor.getBuffer().insert([10,0] ,"extra:SO:extra")
+        editor.setCursorBufferPosition([10,8])
+        autocomplete.attach()
+
+        expect(editor.lineForBufferRow(10)).toBe "extra:sort:extra"
+        expect(editor.getCursorBufferPosition()).toEqual [10,10]
+        expect(editor.getSelection().isEmpty()).toBeTruthy()
+
     describe "when text is selected", ->
       it 'autocompletes word when there is only a prefix', ->
         editor.getBuffer().insert([10,0] ,"extra:sort:extra")
@@ -399,5 +408,3 @@ describe "Autocomplete", ->
 
       editor.trigger 'core:move-up'
       expect(editor.getCursorBufferPosition().row).toBe 0
-
-
diff --git a/src/packages/autocomplete/src/autocomplete.coffee b/src/packages/autocomplete/src/autocomplete.coffee
index 7f9bad470..73d6f66ec 100644
--- a/src/packages/autocomplete/src/autocomplete.coffee
+++ b/src/packages/autocomplete/src/autocomplete.coffee
@@ -185,11 +185,10 @@ class Autocomplete extends View
     {prefix, suffix} = @prefixAndSuffixOfSelection(selection)
 
     if (prefix.length + suffix.length) > 0
-      regex = new RegExp("^#{prefix}(.+)#{suffix}$", "i")
+      regex = new RegExp("^#{prefix}.+#{suffix}$", "i")
       currentWord = prefix + @editor.getSelectedText() + suffix
       for word in @wordList when regex.test(word) and word != currentWord
-        match = regex.exec(word)
-        {prefix, suffix, word, infix: match[1]}
+        {prefix, suffix, word}
     else
       []
 
@@ -197,9 +196,15 @@ class Autocomplete extends View
     selection = @editor.getSelection()
     startPosition = selection.getBufferRange().start
     @isAutocompleting = true
-    @editor.insertText(match.infix)
+    buffer = @editor.getBuffer()
+    @editor.activeEditSession.transact =>
+      selection.deleteSelectedText()
+      buffer.delete(Range.fromPointWithDelta(@editor.getCursorBufferPosition(), 0, -match.prefix.length))
+      buffer.delete(Range.fromPointWithDelta(@editor.getCursorBufferPosition(), 0, match.suffix.length))
+      @editor.insertText(match.word)
 
-    @currentMatchBufferRange = [startPosition, [startPosition.row, startPosition.column + match.infix.length]]
+    infixLength = match.word.length - match.prefix.length - match.suffix.length
+    @currentMatchBufferRange = [startPosition, [startPosition.row, startPosition.column + infixLength]]
     @editor.setSelectedBufferRange(@currentMatchBufferRange)
     @isAutocompleting = false