diff --git a/Python/dynload_mac.c b/Python/dynload_mac.c
index c8c9646..bb5f4fb 100644
--- a/Python/dynload_mac.c
+++ b/Python/dynload_mac.c
@@ -66,7 +66,8 @@
 	err = ResolveAliasFile(&libspec, 1, &isfolder, &didsomething);
 #endif
 	if ( err ) {
-		sprintf(buf, "%.200s: %.200s", pathname, PyMac_StrError(err));
+		PyOS_snprintf(buf, sizeof(buf),
+			      "%.200s: %.200s", pathname, PyMac_StrError(err));
 		PyErr_SetString(PyExc_ImportError, buf);
 		return NULL;
 	}
@@ -91,25 +92,26 @@
 		** the dynamic module was meant for a different Python.
 		*/
 		if (errMessage[0] == 10 && strncmp((char *)errMessage+1, "PythonCore", 10) == 0 ) {
-			sprintf(buf, "Dynamic module was built for %s version of MacPython",
-				(err == cfragImportTooOldErr ? "a newer" : "an older"));
+			PyOS_snprintf(buf, sizeof(buf),
+		      "Dynamic module was built for %s version of MacPython",
+		      (err == cfragImportTooOldErr ? "a newer" : "an older"));
 			PyErr_SetString(PyExc_ImportError, buf);
 			return NULL;
 		}
 	}
 	if ( err ) {
-		sprintf(buf, "%.*s: %.200s",
+		PyOS_snprintf(buf, sizeof(buf), "%.*s: %.200s",
 			errMessage[0], errMessage+1,
 			PyMac_StrError(err));
 		PyErr_SetString(PyExc_ImportError, buf);
 		return NULL;
 	}
 	/* Locate the address of the correct init function */
-	sprintf(funcname, "init%.200s", shortname);
+	PyOS_snprintf(funcname, sizeof(funcname), "init%.200s", shortname);
 	err = FindSymbol(connID, Pstring(funcname), &symAddr, &class);
 	if ( err ) {
-		sprintf(buf, "%s: %.200s",
-			funcname, PyMac_StrError(err));
+		PyOS_snprintf(buf, sizeof(buf), "%s: %.200s",
+			      funcname, PyMac_StrError(err));
 		PyErr_SetString(PyExc_ImportError, buf);
 		return NULL;
 	}