diff --git a/include/CSFML/System/Time.h b/include/CSFML/System/Time.h
index 543a311..e13f59c 100644
--- a/include/CSFML/System/Time.h
+++ b/include/CSFML/System/Time.h
@@ -43,7 +43,7 @@ typedef struct
 /// \brief Predefined "zero" time value
 ///
 ////////////////////////////////////////////////////////////
-CSFML_SYSTEM_API sfTime sfTime_Zero;
+CSFML_SYSTEM_API const sfTime sfTime_Zero;
 
 ////////////////////////////////////////////////////////////
 /// \brief Return a time value as a number of seconds
diff --git a/src/CSFML/System/Time.cpp b/src/CSFML/System/Time.cpp
index e703aa6..8694055 100644
--- a/src/CSFML/System/Time.cpp
+++ b/src/CSFML/System/Time.cpp
@@ -29,7 +29,7 @@
 
 
 ////////////////////////////////////////////////////////////
-sfTime sfTime_Zero = {0};
+const sfTime sfTime_Zero = {0};
 
 
 ////////////////////////////////////////////////////////////