diff --git a/pep-0353.txt b/pep-0353.txt
index 1dc54e134..5e0360d2e 100644
--- a/pep-0353.txt
+++ b/pep-0353.txt
@@ -72,7 +72,7 @@ A new conversion code 'n' is introduced for PyArg_ParseTuple
 and Py_BuildValue, which operates on Py_ssize_t.
 
 The conversion codes 's#' and 't#' will output Py_ssize_t
-if the macro PY_SIZE_T_CLEAN is defined before Python.h
+if the macro PY_SSIZE_T_CLEAN is defined before Python.h
 is included, and continue to output int if that macro
 isn't defined.