diff --git a/ecdsa.go b/ecdsa.go
index 6f5ef48..1d582e6 100644
--- a/ecdsa.go
+++ b/ecdsa.go
@@ -380,7 +380,7 @@ func Add(point1, point2 []byte, name string) (point []byte, isinfinity bool) {
 		return nil, false
 	}
 
-	if x_big.Cmp(big.NewInt(0)) == 0 && x_big.Cmp(big.NewInt(0)) == 0 {
+	if x_big.Cmp(big.NewInt(0)) == 0 && y_big.Cmp(big.NewInt(0)) == 0 {
 		return nil, true
 	}
 
@@ -446,4 +446,4 @@ func Mul(pointin, scalar []byte, name string) (point []byte, isinfinity bool) {
 		y = append([]byte{0x00}, y...)
 	}
 	return append(x, y...), false
-}
\ No newline at end of file
+}