diff --git a/docs/NON-AGENT_API.txt b/docs/NON-AGENT_API.txt
index a6d04da5..22e21b7c 100644
--- a/docs/NON-AGENT_API.txt
+++ b/docs/NON-AGENT_API.txt
@@ -1,4 +1,4 @@
-NON-AGENT API DOCUMENT           Started: 2008-07-24         Updated: 2021-02-27
+NON-AGENT API DOCUMENT           Started: 2008-07-24         Updated: 2021-03-03
 
 This document describes the functions of an API(Application Programming 
 Interface) for all functions NOT directly relating to the VICIDIAL Agent screen. 
@@ -175,6 +175,7 @@ Changes:
 210216-1415 - Added list_exists_check option for add_lead function
 210217-1454 - Added menu_id option for add_did and update_did functions
 210227-1116 - Added xferconf number options to update_campaign, add_list & update_list functions
+210303-1802 - Added list_exists_check option for update_lead function
 
 
 API Functions use the 'function' variable
@@ -1064,6 +1065,7 @@ add_to_hopper -		Y or N, default is N
 remove_from_hopper -	Y or N, default is N
 hopper_priority -	99 to -99, the higher number the higher priority, default is 0
 hopper_local_call_time_check - Y or N, default is N. Validate the local call time and/or state call time before inserting lead in the hopper
+list_exists_check -	Y or N, default is N. If the list_id_field is not a defined list in the system, it will ERROR and not update the lead.
 
 EDITABLE FIELDS- 
 user_field -		1-20 characters, this updates the 'user' field in the vicidial_list table
@@ -1158,6 +1160,7 @@ NOTICE: update_lead NOT REMOVED FROM HOPPER, LEAD IS NOT IN THE HOPPER - 7275551
 ERROR: update_lead INVALID DATA FOR LEAD INSERTION - 6666|||
 ERROR: update_lead NO MATCHES FOUND IN THE SYSTEM - 6666|||
 ERROR: update_lead NO VALID SEARCH METHOD - 6666|SYSTEM|||
+ERROR: update_lead NOT A DEFINED LIST ID, LIST EXISTS CHECK ENABLED - 6666|139
 
 ERROR: update_lead USER DOES NOT HAVE PERMISSION TO UPDATE LEADS IN THE SYSTEM - 6666|0 
 ERROR: update_lead NOT AN ALLOWED LIST ID - 7275551212|98762
diff --git a/www/vicidial/non_agent_api.php b/www/vicidial/non_agent_api.php
index a88d8538..81695f24 100644
--- a/www/vicidial/non_agent_api.php
+++ b/www/vicidial/non_agent_api.php
@@ -164,10 +164,11 @@
 # 210216-1415 - Added list_exists_check option for add_lead function
 # 210217-1454 - Added menu_id option for add_did and update_did functions
 # 210227-1116 - Added xferconf number options to update_campaign, add_list & update_list functions
+# 210303-1802 - Added list_exists_check option for update_lead function
 #
 
-$version = '2.14-141';
-$build = '210227-1116';
+$version = '2.14-142';
+$build = '210303-1802';
 $api_url_log = 0;
 
 $startMS = microtime();
@@ -12121,6 +12122,23 @@ if ($function == 'update_lead')
 						exit;
 						}
 					}
+				if ( (preg_match("/Y/i",$list_exists_check)) and (strlen($list_id_field) > 0) )
+					{
+					$stmt="SELECT count(*) from vicidial_lists where list_id='$list_id_field';";
+					$rslt=mysql_to_mysqli($stmt, $link);
+					$row=mysqli_fetch_row($rslt);
+					if ($DB>0) {echo "DEBUG: update_lead list_exists_check query - $row[0]|$stmt\n";}
+					$list_exists_count = $row[0];
+					if ($list_exists_count < 1)
+						{
+						$result = 'ERROR';
+						$result_reason = "update_lead NOT A DEFINED LIST ID, LIST EXISTS CHECK ENABLED";
+						$data = "$phone_number|$list_id_field";
+						echo "$result: $result_reason - $data\n";
+						api_log($link,$api_logging,$api_script,$user,$agent_user,$function,$value,$result,$result_reason,$source,$data);
+						exit;
+						}
+					}
 
 				if (preg_match("/CAMPAIGN/i",$search_location)) # find lists within campaign
 					{