diff --git a/glm/core/func_exponential.inl b/glm/core/func_exponential.inl
index e76a927e..1b08786d 100644
--- a/glm/core/func_exponential.inl
+++ b/glm/core/func_exponential.inl
@@ -146,6 +146,7 @@ namespace _detail
 	)
 	{
 		GLM_STATIC_ASSERT(detail::type<genType>::is_float, "'inversesqrt' only accept floating-point input");
+		assert(x > genType(0));
 
 		return genType(1) / ::std::sqrt(x);
 	}
diff --git a/readme.txt b/readme.txt
index ff087030..6cfa8579 100644
--- a/readme.txt
+++ b/readme.txt
@@ -42,6 +42,7 @@ GLM 0.9.4.4: 2013-0X-XX
 - Fixed slerp when costheta is close to 1
 - Fixed mat4x2 value_type constructor
 - Fixed glm.natvis for Visual C++ 12 #82
+- Added assert in inversesqrt to detect division by zero. #61
 
 ================================================================================
 GLM 0.9.4.3: 2013-03-20