diff --git a/Misc/NEWS b/Misc/NEWS
index 5ce766435f9..ad25699ecb3 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -322,6 +322,8 @@ Library
 Extension Modules
 -----------------
 
+- Issue #9422: Fix memory leak when re-initializing a struct.Struct object.
+
 - Issue #7900: The getgroups(2) system call on MacOSX behaves rather oddly
   compared to other unix systems. In particular, os.getgroups() does
   not reflect any changes made using os.setgroups() but basicly always
diff --git a/Modules/_struct.c b/Modules/_struct.c
index 936e8af0436..b85d1063685 100644
--- a/Modules/_struct.c
+++ b/Modules/_struct.c
@@ -1404,6 +1404,9 @@ prepare_s(PyStructObject *self)
         PyErr_NoMemory();
         return -1;
     }
+    /* Free any s_codes value left over from a previous initialization. */
+    if (self->s_codes != NULL)
+        PyMem_FREE(self->s_codes);
     self->s_codes = codes;
 
     s = fmt;