diff --git a/ChangeLog b/ChangeLog
index 79efcae520..811946901f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Aug 10 21:18:04 2010  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* complex.c (nucomp_to_[ifr]): don't allow complex with in-exact
+	  imaginary zero to be converted.
+
 Tue Aug 10 20:56:31 2010  Tanaka Akira  <akr@fsij.org>
 
 	* lib/optparse.rb: suppress a warning.
diff --git a/complex.c b/complex.c
index 1052c0c458..b88f6b980b 100644
--- a/complex.c
+++ b/complex.c
@@ -1296,7 +1296,7 @@ nucomp_to_i(VALUE self)
 {
     get_dat1(self);
 
-    if (f_nonzero_p(dat->imag)) {
+    if (k_inexact_p(dat->imag) || f_nonzero_p(dat->imag)) {
 	VALUE s = f_to_s(self);
 	rb_raise(rb_eRangeError, "can't convert %s into Integer",
 		 StringValuePtr(s));
@@ -1315,7 +1315,7 @@ nucomp_to_f(VALUE self)
 {
     get_dat1(self);
 
-    if (f_nonzero_p(dat->imag)) {
+    if (k_inexact_p(dat->imag) || f_nonzero_p(dat->imag)) {
 	VALUE s = f_to_s(self);
 	rb_raise(rb_eRangeError, "can't convert %s into Float",
 		 StringValuePtr(s));
@@ -1334,7 +1334,7 @@ nucomp_to_r(VALUE self)
 {
     get_dat1(self);
 
-    if (f_nonzero_p(dat->imag)) {
+    if (k_inexact_p(dat->imag) || f_nonzero_p(dat->imag)) {
 	VALUE s = f_to_s(self);
 	rb_raise(rb_eRangeError, "can't convert %s into Rational",
 		 StringValuePtr(s));