diff --git a/index/bitmap.go b/index/bitmap.go
index c3395bb3d..881c50a6e 100644
--- a/index/bitmap.go
+++ b/index/bitmap.go
@@ -260,7 +260,7 @@ func Union(a_bm IBitmap, b_bm IBitmap) IBitmap {
 	return output
 }
 
-func AND_NOT(a_bm IBitmap, b_bm IBitmap) IBitmap {
+func Difference(a_bm IBitmap, b_bm IBitmap) IBitmap {
 	var a = a_bm.Min()
 	var b = b_bm.Min()
 	defer a.Close()
diff --git a/index/bitmap_test.go b/index/bitmap_test.go
index 24f966beb..2915ea21d 100644
--- a/index/bitmap_test.go
+++ b/index/bitmap_test.go
@@ -3,6 +3,7 @@ package index
 import (
 	"testing"
 	"time"
+
 	. "github.com/smartystreets/goconvey/convey"
 )
 
@@ -17,17 +18,32 @@ func TestBitmaps(t *testing.T) {
 		So(bc1, ShouldEqual, bc2)
 		So(bc1, ShouldEqual, 4096)
 	})
-	Convey("function AND_NOT 1 and not 0 => true ", t, func() {
+	Convey("function Difference 1 and not 0 => true ", t, func() {
 		bm1 := CreateRBBitmap()
 		bm2 := CreateRBBitmap()
 		SetBit(bm1, 1)
 		//SetBit(bm2,2)
-		all := AND_NOT(bm1, bm2)
+		all := Difference(bm1, bm2)
 		res := BitCount(all)
 
 		So(1, ShouldEqual, res)
 	})
 
+	Convey("function Difference 1 and not 0 => true ", t, func() {
+		bm1 := CreateRBBitmap()
+		bm2 := CreateRBBitmap()
+		SetBit(bm1, 1)
+		SetBit(bm1, 2)
+		SetBit(bm1, 3)
+		SetBit(bm1, 4)
+		SetBit(bm2, 3)
+		//SetBit(bm2,2)
+		all := Difference(bm1, bm2)
+		res := BitCount(all)
+
+		So(3, ShouldEqual, res)
+	})
+
 	Convey("UNION even + odd equal 4096 ", t, func() {
 		even := CreateRBBitmap()
 		for i := uint64(0); i < uint64(4096); i += 2 {
diff --git a/index/commands.go b/index/commands.go
index 0ddcb0d2b..4f27c7483 100644
--- a/index/commands.go
+++ b/index/commands.go
@@ -79,6 +79,19 @@ func (self *CmdUnion) Execute(f *Fragment) Calculation {
 	return f.union(self.bitmap_ids)
 }
 
+type CmdDifference struct {
+	*Responder
+	bitmap_ids []BitmapHandle
+}
+
+func NewDifference(bitmaps []BitmapHandle) *CmdDifference {
+	result := &CmdDifference{NewResponder("Difference"), bitmaps}
+	return result
+}
+func (self *CmdDifference) Execute(f *Fragment) Calculation {
+	return f.difference(self.bitmap_ids)
+}
+
 type CmdIntersect struct {
 	*Responder
 	bitmaps []BitmapHandle
diff --git a/index/fragment_container.go b/index/fragment_container.go
index 771ef0546..1abd38724 100644
--- a/index/fragment_container.go
+++ b/index/fragment_container.go
@@ -115,6 +115,17 @@ func (self *FragmentContainer) Union(frag_id util.SUUID, bh []BitmapHandle) (Bit
 	return 0, errors.New("Invalid Bitmap Handle")
 }
 
+func (self *FragmentContainer) Difference(frag_id util.SUUID, bh []BitmapHandle) (BitmapHandle, error) {
+	if fragment, found := self.GetFragment(frag_id); found {
+		request := NewDifference(bh)
+		fragment.requestChan <- request
+		result := request.Response()
+		util.SendTimer("fragmant_container_Difference", result.exec_time.Nanoseconds())
+		return result.answer.(BitmapHandle), nil
+	}
+	return 0, errors.New("Invalid Bitmap Handle")
+}
+
 func (self *FragmentContainer) Get(frag_id util.SUUID, bitmap_id uint64) (BitmapHandle, error) {
 	if fragment, found := self.GetFragment(frag_id); found {
 		request := NewGet(bitmap_id)
@@ -316,6 +327,7 @@ func (self *Fragment) union(bitmaps []BitmapHandle) BitmapHandle {
 	}
 	return self.AllocHandle(result)
 }
+
 func (self *Fragment) intersect(bitmaps []BitmapHandle) BitmapHandle {
 	var result IBitmap
 	for i, id := range bitmaps {
@@ -328,6 +340,20 @@ func (self *Fragment) intersect(bitmaps []BitmapHandle) BitmapHandle {
 	}
 	return self.AllocHandle(result)
 }
+
+func (self *Fragment) difference(bitmaps []BitmapHandle) BitmapHandle {
+	result := NewBitmap()
+	for i, id := range bitmaps {
+		bm, _ := self.getBitmap(id)
+		if i == 0 {
+			result = bm
+		} else {
+			result = Difference(result, bm)
+		}
+	}
+	return self.AllocHandle(result)
+}
+
 func (self *Fragment) Persist() {
 	err := self.impl.Persist()
 	if err != nil {
diff --git a/index/fragment_container_test.go b/index/fragment_container_test.go
index 9f9a167c6..585f79adf 100644
--- a/index/fragment_container_test.go
+++ b/index/fragment_container_test.go
@@ -6,6 +6,7 @@ import (
 	//	"io/ioutil"
 	//   "time"
 	"pilosa/util"
+
 	. "github.com/smartystreets/goconvey/convey"
 )
 
@@ -35,7 +36,7 @@ func TestFragment(t *testing.T) {
 		So(num, ShouldEqual, 1)
 	})
 
-	Convey("Union/Intersect", t, func() {
+	Convey("Union/Intersect/Difference", t, func() {
 		bi1 := uint64(1234)
 		bi2 := uint64(4321)
 
@@ -53,6 +54,11 @@ func TestFragment(t *testing.T) {
 
 		num, _ = dummy.Count(general, result)
 		So(num, ShouldEqual, 0)
+
+		result, _ = dummy.Difference(general, handles)
+		num, _ = dummy.Count(general, result)
+		So(num, ShouldEqual, 1)
+
 	})
 	Convey("Union Empty", t, func() {