diff --git a/src/redis.c b/src/redis.c
index a76a56185..8cb18e91d 100644
--- a/src/redis.c
+++ b/src/redis.c
@@ -216,7 +216,7 @@ struct redisCommand redisCommandTable[] = {
     {"sync",syncCommand,1,"ars",0,NULL,0,0,0,0,0},
     {"flushdb",flushdbCommand,1,"w",0,NULL,0,0,0,0,0},
     {"flushall",flushallCommand,1,"w",0,NULL,0,0,0,0,0},
-    {"sort",sortCommand,-2,"wm",0,NULL,1,1,1,0,0},
+    {"sort",sortCommand,-2,"wmS",0,NULL,1,1,1,0,0},
     {"info",infoCommand,-1,"r",0,NULL,0,0,0,0,0},
     {"monitor",monitorCommand,1,"ars",0,NULL,0,0,0,0,0},
     {"ttl",ttlCommand,2,"r",0,NULL,1,1,1,0,0},
diff --git a/src/redis.h b/src/redis.h
index 3a5e3d4a8..2fcdcb4d9 100644
--- a/src/redis.h
+++ b/src/redis.h
@@ -627,6 +627,7 @@ struct redisServer {
     list *unblocked_clients; /* list of clients to unblock before next loop */
     /* Sort parameters - qsort_r() is only available under BSD so we
      * have to take this state global, in order to pass it to sortCompare() */
+    int sort_dontsort;
     int sort_desc;
     int sort_alpha;
     int sort_bypattern;
diff --git a/src/scripting.c b/src/scripting.c
index 92fb928a2..2eac840c5 100644
--- a/src/scripting.c
+++ b/src/scripting.c
@@ -140,7 +140,22 @@ void luaSortArray(lua_State *lua) {
     lua_pushstring(lua,"sort");
     lua_gettable(lua,-2);       /* Stack: array, table, table.sort */
     lua_pushvalue(lua,-3);      /* Stack: array, table, table.sort, array */
-    lua_call(lua,1,0);          /* Stack: array (sorted), table */
+    if (lua_pcall(lua,1,0,0)) {
+        /* Stack: array, table, error */
+
+        /* We are not interested in the error, we assume that the problem is
+         * that there are 'false' elements inside the array, so we try
+         * again with a slower function but able to handle this case, that
+         * is: table.sort(table, __redis__compare_helper) */
+        lua_pop(lua,1);             /* Stack: array, table */
+        lua_pushstring(lua,"sort"); /* Stack: array, table, sort */
+        lua_gettable(lua,-2);       /* Stack: array, table, table.sort */
+        lua_pushvalue(lua,-3);      /* Stack: array, table, table.sort, array */
+        lua_getglobal(lua,"__redis__compare_helper");
+        /* Stack: array, table, table.sort, array, __redis__compare_helper */
+        lua_call(lua,2,0);
+    }
+    /* Stack: array (sorted), table */
     lua_pop(lua,1);             /* Stack: array (sorted) */
 }
 
@@ -228,7 +243,9 @@ int luaRedisGenericCommand(lua_State *lua, int raise_error) {
      * reply as expected. */
     if ((cmd->flags & REDIS_CMD_SORT_FOR_SCRIPT) &&
         (reply[0] == '*' && reply[1] != '-')) {
-        luaSortArray(lua);
+        /* Skip this step if command is SORT but output was already sorted */
+        if (cmd->proc != sortCommand || server.sort_dontsort)
+            luaSortArray(lua);
     }
     sdsfree(reply);
 
@@ -403,6 +420,18 @@ void scriptingInit(void) {
 
     lua_setglobal(lua,"math");
 
+    /* Add a helper funciton that we use to sort the multi bulk output of non
+     * deterministic commands, when containing 'false' elements. */
+    {
+        char *compare_func =    "function __redis__compare_helper(a,b)\n"
+                                "  if a == false then a = '' end\n"
+                                "  if b == false then b = '' end\n"
+                                "  return a<b\n"
+                                "end\n";
+        luaL_loadbuffer(lua,compare_func,strlen(compare_func),"cmp_func_def");
+        lua_pcall(lua,0,0,0);
+    }
+
     /* Create the (non connected) client that we use to execute Redis commands
      * inside the Lua interpreter.
      * Note: there is no need to create it again when this function is called
diff --git a/src/sort.c b/src/sort.c
index 038aec27a..11b73ad38 100644
--- a/src/sort.c
+++ b/src/sort.c
@@ -1,5 +1,6 @@
 #include "redis.h"
 #include "pqsort.h" /* Partial qsort for SORT+LIMIT */
+#include <math.h> /* isnan() */
 
 redisSortOperation *createSortOperation(int type, robj *pattern) {
     redisSortOperation *so = zmalloc(sizeof(*so));
@@ -102,7 +103,10 @@ int sortCompare(const void *s1, const void *s2) {
         } else if (so1->u.score < so2->u.score) {
             cmp = -1;
         } else {
-            cmp = 0;
+            /* Objects have the same score, but we don't want the comparison
+             * to be undefined, so we compare objects lexicographycally.
+             * This way the result of SORT is deterministic. */
+            cmp = compareStringObjects(so1->obj,so2->obj);
         }
     } else {
         /* Alphanumeric sorting */
@@ -136,6 +140,7 @@ void sortCommand(redisClient *c) {
     long limit_start = 0, limit_count = -1, start, end;
     int j, dontsort = 0, vectorlen;
     int getop = 0; /* GET operation counter */
+    int int_convertion_error = 0;
     robj *sortval, *sortby = NULL, *storekey = NULL;
     redisSortObject *vector; /* Resulting vector to sort */
 
@@ -266,7 +271,14 @@ void sortCommand(redisClient *c) {
                 if (sortby) vector[j].u.cmpobj = getDecodedObject(byval);
             } else {
                 if (byval->encoding == REDIS_ENCODING_RAW) {
-                    vector[j].u.score = strtod(byval->ptr,NULL);
+                    char *eptr;
+
+                    vector[j].u.score = strtod(byval->ptr,&eptr);
+                    if (eptr[0] != '\0' || errno == ERANGE ||
+                        isnan(vector[j].u.score))
+                    {
+                        int_convertion_error = 1;
+                    }
                 } else if (byval->encoding == REDIS_ENCODING_INT) {
                     /* Don't need to decode the object if it's
                      * integer-encoded (the only encoding supported) so
@@ -295,6 +307,7 @@ void sortCommand(redisClient *c) {
     }
     if (end >= vectorlen) end = vectorlen-1;
 
+    server.sort_dontsort = dontsort;
     if (dontsort == 0) {
         server.sort_desc = desc;
         server.sort_alpha = alpha;
@@ -308,7 +321,9 @@ void sortCommand(redisClient *c) {
     /* Send command output to the output buffer, performing the specified
      * GET/DEL/INCR/DECR operations if any. */
     outputlen = getop ? getop*(end-start+1) : end-start+1;
-    if (storekey == NULL) {
+    if (int_convertion_error) {
+        addReplyError(c,"One or more scores can't be converted into double");
+    } else if (storekey == NULL) {
         /* STORE option not specified, sent the sorting result to client */
         addReplyMultiBulkLen(c,outputlen);
         for (j = start; j <= end; j++) {
diff --git a/tests/unit/sort.tcl b/tests/unit/sort.tcl
index 388130659..a50f04736 100644
--- a/tests/unit/sort.tcl
+++ b/tests/unit/sort.tcl
@@ -146,7 +146,7 @@ start_server {
     test "SORT with STORE does not create empty lists (github issue 224)" {
         r flushdb
         r lpush foo bar
-        r sort foo limit 10 10 store zap
+        r sort foo alpha limit 10 10 store zap
         r exists zap
     } {0}