diff --git a/items.c b/items.c
--- a/items.c
+++ b/items.c
@@ -17,6 +17,7 @@
 /* Forward Declarations */
 static void item_link_q(item *it);
 static void item_unlink_q(item *it);
+static uint64_t get_cas_id();
 
 /*
  * We only reposition items in the LRU queue if they haven't been repositioned
@@ -37,6 +38,15 @@ void item_init(void) {
         tails[i] = NULL;
         sizes[i] = 0;
     }
+}
+
+/* Get the next CAS id for a new item. */
+uint64_t get_cas_id() {
+    static uint64_t cas_id;
+    if(cas_id >= MAX_CAS_ID) {
+        cas_id = 0;
+    }
+    return ++cas_id;
 }
 
 /* Enable this for reference-count debugging. */
@@ -129,6 +139,7 @@ item *do_item_alloc(char *key, const siz
     it->it_flags = 0;
     it->nkey = nkey;
     it->nbytes = nbytes;
+    it->cas_id = get_cas_id();
     strcpy(ITEM_key(it), key);
     it->exptime = exptime;
     memcpy(ITEM_suffix(it), suffix, (size_t)nsuffix);
diff --git a/memcached.c b/memcached.c
--- a/memcached.c
+++ b/memcached.c
@@ -1079,7 +1079,6 @@ static inline void process_get_command(c
     item *it;
     token_t *key_token = &tokens[KEY_TOKEN];
     char suffix[255];
-    uint32_t in_memory_ptr;
     assert(c != NULL);
 
     if (settings.managed) {
@@ -1132,8 +1131,8 @@ static inline void process_get_command(c
 
                 if(return_key_ptr == true)
                 {
-                  in_memory_ptr = (uint32_t)item_get(key, nkey);
-                  sprintf(suffix," %d %d %lu\r\n", atoi(ITEM_suffix(it) + 1), it->nbytes - 2, in_memory_ptr);
+                  sprintf(suffix," %d %d %llu\r\n", atoi(ITEM_suffix(it) + 1),
+				  	it->nbytes - 2, it->cas_id);
                   if (add_iov(c, "VALUE ", 6) != 0 ||
                       add_iov(c, ITEM_key(it), it->nkey) != 0 ||
                       add_iov(c, suffix, strlen(suffix)) != 0 ||
@@ -1207,7 +1206,7 @@ static void process_update_command(conn 
     int flags;
     time_t exptime;
     int vlen, old_vlen;
-    uint32_t req_memory_ptr, in_memory_ptr;
+    uint32_t req_cas_id;
     item *it, *old_it;
 
     assert(c != NULL);
@@ -1227,7 +1226,7 @@ static void process_update_command(conn 
     // does cas value exist?
     if(tokens[5].value)
     {
-      req_memory_ptr = strtoull(tokens[5].value, NULL, 10);
+      req_cas_id = strtoull(tokens[5].value, NULL, 10);
     }
 
     if(errno == ERANGE || ((flags == 0 || exptime == 0) && errno == EINVAL)) {
@@ -1255,35 +1254,30 @@ static void process_update_command(conn 
     it = item_alloc(key, nkey, flags, realtime(exptime), vlen+2);
 
     /* HANDLE_CAS VALIDATION */
-    if (handle_cas == true)
-    {
-      item *itmp=item_get(key, it->nkey);
-      /* Release the reference */
-      if(itmp) {
-        item_remove(itmp);
-      }
-      in_memory_ptr = (uint32_t)itmp;
-      if(in_memory_ptr == req_memory_ptr)
-      {
-        // validates allow the set
-      }
-      else if(in_memory_ptr)
-      {
-        out_string(c, "EXISTS");
+    if (handle_cas == true) {
+      	item *itmp=item_get(key, it->nkey);
+      	if(itmp && itmp->cas_id == req_cas_id) {
+        	// validates allow the set
+      		if(itmp) {
+        		item_remove(itmp);
+      		}
+      	} else if(itmp) {
+        	out_string(c, "EXISTS");
 
-        /* swallow the data line */
-        c->write_and_go = conn_swallow;
-        c->sbytes = vlen + 2;
-        return;
-      }
-      else
-      {
-        out_string(c, "NOT FOUND");
-        /* swallow the data line */
-        c->write_and_go = conn_swallow;
-        c->sbytes = vlen + 2;
-        return;
-      }
+        	/* swallow the data line */
+        	c->write_and_go = conn_swallow;
+        	c->sbytes = vlen + 2;
+      		if(itmp) {
+        		item_remove(itmp);
+      		}
+        	return;
+      	} else {
+        	out_string(c, "NOT FOUND");
+        	/* swallow the data line */
+        	c->write_and_go = conn_swallow;
+        	c->sbytes = vlen + 2;
+        	return;
+      	}
     }
 
     if (it == 0) {
diff --git a/memcached.h b/memcached.h
--- a/memcached.h
+++ b/memcached.h
@@ -31,6 +31,8 @@
 #define ITEM_LIST_HIGHWAT 400
 #define IOV_LIST_HIGHWAT 600
 #define MSG_LIST_HIGHWAT 100
+
+#define MAX_CAS_ID 0x7ffffffffffffff0
 
 /* Get a consistent bool type */
 #if HAVE_STDBOOL_H
@@ -111,6 +113,7 @@ typedef struct _stritem {
     uint8_t         it_flags;   /* ITEM_* above */
     uint8_t         slabs_clsid;/* which slab class we're in */
     uint8_t         nkey;       /* key length, w/terminating null and padding */
+	uint64_t        cas_id;     /* the CAS identifier */
     void * end[];
     /* then null-terminated key */
     /* then " flags length\r\n" (no terminating null) */