diff --git a/src/cpu_timer.cpp b/src/cpu_timer.cpp
index 82a8d7b..fd6f2bc 100644
--- a/src/cpu_timer.cpp
+++ b/src/cpu_timer.cpp
@@ -34,7 +34,6 @@
 
 using boost::timer::nanosecond_type;
 using boost::timer::cpu_times;
-using boost::system::error_code;
 
 namespace
 {