diff --git a/ChangeLog b/ChangeLog
index 02698e5a25..37d184bb4a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Jan  5 12:49:39 2005  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* eval.c (rb_thread_initialize): Thread objects cannot be initialized
+	  again.  fixed: [ruby-core:04067]
+
 Wed Jan  5 10:48:16 2005  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* dir.c (dir_s_mkdir): win32 special processing doesn't need any
diff --git a/eval.c b/eval.c
index eb0fa3873b..3f0dec822a 100644
--- a/eval.c
+++ b/eval.c
@@ -11567,10 +11567,21 @@ static VALUE
 rb_thread_initialize(thread, args)
     VALUE thread, args;
 {
+    rb_thread_t th;
+
     if (!rb_block_given_p()) {
 	rb_raise(rb_eThreadError, "must be called with a block");
     }
-    return rb_thread_start_0(rb_thread_yield, args, rb_thread_check(thread));
+    th = rb_thread_check(thread);
+    if (th->stk_max) {
+	NODE *node = th->node;
+	if (!node) {
+	    rb_raise(rb_eThreadError, "already initialized thread");
+	}
+	rb_raise(rb_eThreadError, "already initialized thread - %s:%d",
+		 node->nd_file, nd_line(node));
+    }
+    return rb_thread_start_0(rb_thread_yield, args, th);
 }