diff --git a/mrbgems/math.gembox b/mrbgems/math.gembox
index d2947314e..b07842481 100644
--- a/mrbgems/math.gembox
+++ b/mrbgems/math.gembox
@@ -7,8 +7,6 @@ MRuby::GemBox.new do |conf|
   # Use Rational/Complex numbers
   conf.gem :core => "mruby-rational"
   conf.gem :core => "mruby-complex"
-  # Use Complex math functions in CMath module
-  conf.gem :core => "mruby-cmath"
   # Use Multi-precision Integer
   conf.gem :core => "mruby-bigint"
 end