diff --git a/generator.go b/generator.go
index b1833a0..3f2f1da 100644
--- a/generator.go
+++ b/generator.go
@@ -107,7 +107,7 @@ func (g *generator) NewV1() UUID {
 	copy(u[10:], hardwareAddr)
 
 	u.SetVersion(V1)
-	u.SetVariant()
+	u.SetVariant(VariantRFC4122)
 
 	return u
 }
@@ -133,7 +133,7 @@ func (g *generator) NewV2(domain byte) UUID {
 	copy(u[10:], hardwareAddr)
 
 	u.SetVersion(V2)
-	u.SetVariant()
+	u.SetVariant(VariantRFC4122)
 
 	return u
 }
@@ -142,7 +142,7 @@ func (g *generator) NewV2(domain byte) UUID {
 func (g *generator) NewV3(ns UUID, name string) UUID {
 	u := newFromHash(md5.New(), ns, name)
 	u.SetVersion(V3)
-	u.SetVariant()
+	u.SetVariant(VariantRFC4122)
 
 	return u
 }
@@ -152,7 +152,7 @@ func (g *generator) NewV4() UUID {
 	u := UUID{}
 	g.safeRandom(u[:])
 	u.SetVersion(V4)
-	u.SetVariant()
+	u.SetVariant(VariantRFC4122)
 
 	return u
 }
@@ -161,7 +161,7 @@ func (g *generator) NewV4() UUID {
 func (g *generator) NewV5(ns UUID, name string) UUID {
 	u := newFromHash(sha1.New(), ns, name)
 	u.SetVersion(V5)
-	u.SetVariant()
+	u.SetVariant(VariantRFC4122)
 
 	return u
 }
diff --git a/uuid.go b/uuid.go
index 62e127b..a2b8e2c 100644
--- a/uuid.go
+++ b/uuid.go
@@ -92,14 +92,17 @@ func (u UUID) Version() byte {
 // Variant returns UUID layout variant.
 func (u UUID) Variant() byte {
 	switch {
-	case (u[8] & 0x80) == 0x00:
+	case (u[8] >> 7) == 0x00:
 		return VariantNCS
-	case (u[8]&0xc0)|0x80 == 0x80:
+	case (u[8] >> 6) == 0x02:
 		return VariantRFC4122
-	case (u[8]&0xe0)|0xc0 == 0xc0:
+	case (u[8] >> 5) == 0x06:
 		return VariantMicrosoft
+	case (u[8] >> 5) == 0x07:
+		fallthrough
+	default:
+		return VariantFuture
 	}
-	return VariantFuture
 }
 
 // Bytes returns bytes slice representation of UUID.
@@ -130,9 +133,20 @@ func (u *UUID) SetVersion(v byte) {
 	u[6] = (u[6] & 0x0f) | (v << 4)
 }
 
-// SetVariant sets variant bits as described in RFC 4122.
-func (u *UUID) SetVariant() {
-	u[8] = (u[8] & 0xbf) | 0x80
+// SetVariant sets variant bits.
+func (u *UUID) SetVariant(v byte) {
+	switch v {
+	case VariantNCS:
+		u[8] = (u[8]&(0xff>>1) | (0x00 << 7))
+	case VariantRFC4122:
+		u[8] = (u[8]&(0xff>>2) | (0x02 << 6))
+	case VariantMicrosoft:
+		u[8] = (u[8]&(0xff>>3) | (0x06 << 5))
+	case VariantFuture:
+		fallthrough
+	default:
+		u[8] = (u[8]&(0xff>>3) | (0x07 << 5))
+	}
 }
 
 // Must is a helper that wraps a call to a function returning (UUID, error)
diff --git a/uuid_test.go b/uuid_test.go
index 6ae0079..beb336d 100644
--- a/uuid_test.go
+++ b/uuid_test.go
@@ -79,6 +79,12 @@ func (s *testSuite) TestVariant(c *C) {
 
 func (s *testSuite) TestSetVariant(c *C) {
 	u := UUID{}
-	u.SetVariant()
+	u.SetVariant(VariantNCS)
+	c.Assert(u.Variant(), Equals, VariantNCS)
+	u.SetVariant(VariantRFC4122)
 	c.Assert(u.Variant(), Equals, VariantRFC4122)
+	u.SetVariant(VariantMicrosoft)
+	c.Assert(u.Variant(), Equals, VariantMicrosoft)
+	u.SetVariant(VariantFuture)
+	c.Assert(u.Variant(), Equals, VariantFuture)
 }