diff --git a/include/picrin.h b/include/picrin.h
index 5db83684..6f0184a8 100644
--- a/include/picrin.h
+++ b/include/picrin.h
@@ -145,7 +145,6 @@ pic_value pic_funcall(pic_state *pic, const char *name, pic_list args);
 struct pic_proc *pic_get_proc(pic_state *);
 int pic_get_args(pic_state *, const char *, ...);
 void pic_defun(pic_state *, const char *, pic_func_t);
-void pic_defmacro(pic_state *, const char *, struct pic_proc *);
 
 bool pic_equal_p(pic_state *, pic_value, pic_value);