diff --git a/dlls/msvcrt/mbcs.c b/dlls/msvcrt/mbcs.c
index d00c31af4cf..edf919c435d 100644
--- a/dlls/msvcrt/mbcs.c
+++ b/dlls/msvcrt/mbcs.c
@@ -2006,27 +2006,19 @@ int CDECL _mbsupr_s(unsigned char* s, MSVCRT_size_t len)
 MSVCRT_size_t CDECL _mbsspn(const unsigned char* string, const unsigned char* set)
 {
     const unsigned char *p, *q;
+    unsigned int pc, qc;
 
     for (p = string; *p; p++)
     {
-        if (_ismbblead(*p))
+        pc = _mbsnextc(p);
+        for (q = set; *q; q++)
         {
-            for (q = set; *q; q += 2)
-            {
-                if (!q[1])
-                    break;
-                if ((*p == *q) &&  (p[1] == q[1]))
-                    break;
-            }
-            if (!q[0] || !q[1]) break;
-        }
-        else
-        {
-            for (q = set; *q; q++)
-                if (*p == *q)
-                    break;
-            if (!*q) break;
+            qc = _mbsnextc(q);
+            if (pc == qc) break;
+            if (qc > 255 && q[1]) q++;
         }
+        if (!*q) break;
+        if (pc > 255 && p[1]) p++;
     }
     return p - string;
 }
diff --git a/dlls/msvcrt/tests/string.c b/dlls/msvcrt/tests/string.c
index 154b9644852..7fe6474e2bc 100644
--- a/dlls/msvcrt/tests/string.c
+++ b/dlls/msvcrt/tests/string.c
@@ -530,13 +530,13 @@ static void test_mbsspn( void)
 
     _setmbcp( 932);
     ret=_mbsspn( mbstr, mbset1);
-    todo_wine ok( ret==8, "_mbsspn returns %d should be 8\n", ret);
+    ok( ret==8, "_mbsspn returns %d should be 8\n", ret);
     ret=_mbsspn( mbstr, mbset2);
     ok( ret==1, "_mbsspn returns %d should be 1\n", ret);
     ret=_mbsspn( mbstr+8, mbset1);
     ok( ret==0, "_mbsspn returns %d should be 0\n", ret);
     ret=_mbsspn( mbstr+8, mbset2);
-    todo_wine ok( ret==2, "_mbsspn returns %d should be 2\n", ret);
+    ok( ret==2, "_mbsspn returns %d should be 2\n", ret);
 
     _setmbcp( cp);
 }