diff --git a/dlls/rpcrt4/rpcrt4_main.c b/dlls/rpcrt4/rpcrt4_main.c
index 6a5c504e1ac..c8b332b78e8 100644
--- a/dlls/rpcrt4/rpcrt4_main.c
+++ b/dlls/rpcrt4/rpcrt4_main.c
@@ -419,22 +419,96 @@ RPC_STATUS WINAPI UuidToStringA(UUID *Uuid, LPSTR* StringUuid)
   return RPC_S_OK;
 }
 
+
+static const BYTE hex2bin[] =
+{
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,        /* 0x00 */
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,        /* 0x10 */
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,        /* 0x20 */
+    0,1,2,3,4,5,6,7,8,9,0,0,0,0,0,0,        /* 0x30 */
+    0,10,11,12,13,14,15,0,0,0,0,0,0,0,0,0,  /* 0x40 */
+    0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,        /* 0x50 */
+    0,10,11,12,13,14,15                     /* 0x60 */
+};
+
 /***********************************************************************
  *		UuidFromStringA (RPCRT4.@)
  */
 RPC_STATUS WINAPI UuidFromStringA(LPSTR str, UUID *uuid)
 {
-    FIXME("%s %p\n",debugstr_a(str),uuid);
-    return RPC_S_INVALID_STRING_UUID;
+    BYTE *s = (BYTE *)str;
+    int i;
+
+    if (!s) return UuidCreateNil( uuid );
+
+    if (strlen(s) != 36) return RPC_S_INVALID_STRING_UUID;
+
+    if ((s[8]!='-') || (s[13]!='-') || (s[18]!='-') || (s[23]!='-'))
+        return RPC_S_INVALID_STRING_UUID;
+
+    for (i=0; i<36; i++)
+    {
+        if ((i == 8)||(i == 13)||(i == 18)||(i == 23)) continue;
+        if (s[i] > 'f' || (!hex2bin[s[i]] && s[i] != '0')) return RPC_S_INVALID_STRING_UUID;
+    }
+
+    /* in form XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX */
+
+    uuid->Data1 = (hex2bin[s[0]] << 28 | hex2bin[s[1]] << 24 | hex2bin[s[2]] << 20 | hex2bin[s[3]] << 16 |
+                   hex2bin[s[4]] << 12 | hex2bin[s[5]]  << 8 | hex2bin[s[6]]  << 4 | hex2bin[s[7]]);
+    uuid->Data2 =  hex2bin[s[9]] << 12 | hex2bin[s[10]] << 8 | hex2bin[s[11]] << 4 | hex2bin[s[12]];
+    uuid->Data3 = hex2bin[s[14]] << 12 | hex2bin[s[15]] << 8 | hex2bin[s[16]] << 4 | hex2bin[s[17]];
+
+    /* these are just sequential bytes */
+    uuid->Data4[0] = hex2bin[s[19]] << 4 | hex2bin[s[20]];
+    uuid->Data4[1] = hex2bin[s[21]] << 4 | hex2bin[s[22]];
+    uuid->Data4[2] = hex2bin[s[24]] << 4 | hex2bin[s[25]];
+    uuid->Data4[3] = hex2bin[s[26]] << 4 | hex2bin[s[27]];
+    uuid->Data4[4] = hex2bin[s[28]] << 4 | hex2bin[s[29]];
+    uuid->Data4[5] = hex2bin[s[30]] << 4 | hex2bin[s[31]];
+    uuid->Data4[6] = hex2bin[s[32]] << 4 | hex2bin[s[33]];
+    uuid->Data4[7] = hex2bin[s[34]] << 4 | hex2bin[s[35]];
+    return RPC_S_OK;
 }
 
+
 /***********************************************************************
  *		UuidFromStringW (RPCRT4.@)
  */
-RPC_STATUS WINAPI UuidFromStringW(LPWSTR str, UUID *uuid)
+RPC_STATUS WINAPI UuidFromStringW(LPWSTR s, UUID *uuid)
 {
-    FIXME("%s %p\n",debugstr_w(str),uuid);
-    return RPC_S_INVALID_STRING_UUID;
+    int i;
+
+    if (!s) return UuidCreateNil( uuid );
+
+    if (strlenW(s) != 36) return RPC_S_INVALID_STRING_UUID;
+
+    if ((s[8]!='-') || (s[13]!='-') || (s[18]!='-') || (s[23]!='-'))
+        return RPC_S_INVALID_STRING_UUID;
+
+    for (i=0; i<36; i++)
+    {
+        if ((i == 8)||(i == 13)||(i == 18)||(i == 23)) continue;
+        if (s[i] > 'f' || (!hex2bin[s[i]] && s[i] != '0')) return RPC_S_INVALID_STRING_UUID;
+    }
+
+    /* in form XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX */
+
+    uuid->Data1 = (hex2bin[s[0]] << 28 | hex2bin[s[1]] << 24 | hex2bin[s[2]] << 20 | hex2bin[s[3]] << 16 |
+                   hex2bin[s[4]] << 12 | hex2bin[s[5]]  << 8 | hex2bin[s[6]]  << 4 | hex2bin[s[7]]);
+    uuid->Data2 =  hex2bin[s[9]] << 12 | hex2bin[s[10]] << 8 | hex2bin[s[11]] << 4 | hex2bin[s[12]];
+    uuid->Data3 = hex2bin[s[14]] << 12 | hex2bin[s[15]] << 8 | hex2bin[s[16]] << 4 | hex2bin[s[17]];
+
+    /* these are just sequential bytes */
+    uuid->Data4[0] = hex2bin[s[19]] << 4 | hex2bin[s[20]];
+    uuid->Data4[1] = hex2bin[s[21]] << 4 | hex2bin[s[22]];
+    uuid->Data4[2] = hex2bin[s[24]] << 4 | hex2bin[s[25]];
+    uuid->Data4[3] = hex2bin[s[26]] << 4 | hex2bin[s[27]];
+    uuid->Data4[4] = hex2bin[s[28]] << 4 | hex2bin[s[29]];
+    uuid->Data4[5] = hex2bin[s[30]] << 4 | hex2bin[s[31]];
+    uuid->Data4[6] = hex2bin[s[32]] << 4 | hex2bin[s[33]];
+    uuid->Data4[7] = hex2bin[s[34]] << 4 | hex2bin[s[35]];
+    return RPC_S_OK;
 }
 
 /***********************************************************************