diff --git a/src/nbla/cuda/function/generic/log_sigmoid.cu b/src/nbla/cuda/function/generic/log_sigmoid.cu
index 96998d18d..0fcb0bd63 100644
--- a/src/nbla/cuda/function/generic/log_sigmoid.cu
+++ b/src/nbla/cuda/function/generic/log_sigmoid.cu
@@ -22,7 +22,6 @@
 #include <cmath>
 
 namespace nbla {
-NBLA_DEFINE_TRANSFORM_UNARY_CUDA(LogSigmoid,
-                                 std::log((T)1 / (std::exp(-x) + (T)1)),
+NBLA_DEFINE_TRANSFORM_UNARY_CUDA(LogSigmoid, -std::log(std::exp(-x) + (T)1),
                                  (T)1 / (std::exp(x) + (T)1));
 }