diff --git a/include/hpp/fcl/math/transform.h b/include/hpp/fcl/math/transform.h
index 56c14c9b27fec7c42bea5c1cb8c9cfb81f4f6e9e..bd5d6d80b37141a8ad765afa74bbe87db195bc12 100644
--- a/include/hpp/fcl/math/transform.h
+++ b/include/hpp/fcl/math/transform.h
@@ -148,10 +148,6 @@ public:
     return *this;
   }
 
-  /// @brief minus
-  Quaternion3f operator - (const Quaternion3f& other) const;
-  const Quaternion3f& operator -= (const Quaternion3f& other);
-
   /// @brief multiplication
   inline Quaternion3f operator * (const Quaternion3f& other) const
   {