diff --git a/complex.c b/complex.c
index 4737891270..3965f3dd2d 100644
--- a/complex.c
+++ b/complex.c
@@ -1446,20 +1446,6 @@ rb_Complex(VALUE x, VALUE y)
     return nucomp_s_convert(2, a, rb_cComplex);
 }
 
-VALUE
-rb_complex_set_real(VALUE cmp, VALUE r)
-{
-    RCOMPLEX_SET_REAL(cmp, r);
-    return cmp;
-}
-
-VALUE
-rb_complex_set_imag(VALUE cmp, VALUE i)
-{
-    RCOMPLEX_SET_IMAG(cmp, i);
-    return cmp;
-}
-
 VALUE
 rb_complex_abs(VALUE cmp)
 {
diff --git a/include/ruby/backward.h b/include/ruby/backward.h
index 2a92df38d2..0ae9911da8 100644
--- a/include/ruby/backward.h
+++ b/include/ruby/backward.h
@@ -4,6 +4,10 @@
 #define DECLARE_DEPRECATED_FEATURE(ver, func) \
     NORETURN(ERRORFUNC(("deprecated since "#ver), DEPRECATED(void func(void))))
 
+/* complex.c */
+DECLARE_DEPRECATED_FEATURE(2.2, rb_complex_set_real);
+DECLARE_DEPRECATED_FEATURE(2.2, rb_complex_set_imag);
+
 /* eval.c */
 DECLARE_DEPRECATED_FEATURE(2.2, rb_disable_super);
 DECLARE_DEPRECATED_FEATURE(2.2, rb_enable_super);
diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index 2f6afaa0c3..d9aecf3446 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -183,8 +183,6 @@ VALUE rb_complex_polar(VALUE, VALUE);
 VALUE rb_Complex(VALUE, VALUE);
 #define rb_Complex1(x) rb_Complex((x), INT2FIX(0))
 #define rb_Complex2(x,y) rb_Complex((x), (y))
-DEPRECATED(VALUE rb_complex_set_real(VALUE, VALUE));
-DEPRECATED(VALUE rb_complex_set_imag(VALUE, VALUE));
 /* class.c */
 VALUE rb_class_new(VALUE);
 VALUE rb_mod_init_copy(VALUE, VALUE);