diff --git a/Objects/stringlib/ucs2lib.h b/Objects/stringlib/ucs2lib.h
index 18117ef5e65..e2e8c1be0fe 100644
--- a/Objects/stringlib/ucs2lib.h
+++ b/Objects/stringlib/ucs2lib.h
@@ -18,7 +18,7 @@
 #define STRINGLIB_TOUPPER        Py_UNICODE_TOUPPER
 #define STRINGLIB_TOLOWER        Py_UNICODE_TOLOWER
 #define STRINGLIB_FILL           Py_UNICODE_FILL
-#define STRINGLIB_STR            PyUnicode_1BYTE_DATA
+#define STRINGLIB_STR            PyUnicode_2BYTE_DATA
 #define STRINGLIB_LEN            PyUnicode_GET_LENGTH
 #define STRINGLIB_NEW            _PyUnicode_FromUCS2
 #define STRINGLIB_RESIZE         not_supported
diff --git a/Objects/stringlib/ucs4lib.h b/Objects/stringlib/ucs4lib.h
index 988ddc08d8f..0ca86604767 100644
--- a/Objects/stringlib/ucs4lib.h
+++ b/Objects/stringlib/ucs4lib.h
@@ -18,7 +18,7 @@
 #define STRINGLIB_TOUPPER        Py_UNICODE_TOUPPER
 #define STRINGLIB_TOLOWER        Py_UNICODE_TOLOWER
 #define STRINGLIB_FILL           Py_UNICODE_FILL
-#define STRINGLIB_STR            PyUnicode_1BYTE_DATA
+#define STRINGLIB_STR            PyUnicode_4BYTE_DATA
 #define STRINGLIB_LEN            PyUnicode_GET_LENGTH
 #define STRINGLIB_NEW            _PyUnicode_FromUCS4
 #define STRINGLIB_RESIZE         not_supported