diff --git a/include/MySQL_Thread.h b/include/MySQL_Thread.h
index e1915a549a..721926ee0d 100644
--- a/include/MySQL_Thread.h
+++ b/include/MySQL_Thread.h
@@ -25,7 +25,6 @@
 #define SQLITE_HOSTGROUP -4
 
 
-#define MYSQL_DEFAULT_TX_ISOLATION	"READ-COMMITTED"
 #define MYSQL_DEFAULT_SESSION_TRACK_GTIDS      "OFF"
 #define MYSQL_DEFAULT_COLLATION_CONNECTION	""
 #define MYSQL_DEFAULT_NET_WRITE_TIMEOUT	"60"
@@ -509,7 +508,6 @@ class MySQL_Threads_Handler
 		char *init_connect;
 		char *ldap_user_variable;
 		char *add_ldap_user_comment;
-		char *default_tx_isolation;
 		char *default_session_track_gtids;
 		char *default_variables[SQL_NAME_LAST_LOW_WM];
 		char *firewall_whitelist_errormsg;
diff --git a/include/proxysql_structs.h b/include/proxysql_structs.h
index 67205cbb09..97080cad67 100644
--- a/include/proxysql_structs.h
+++ b/include/proxysql_structs.h
@@ -778,7 +778,6 @@ __thread char *mysql_thread___server_version;
 __thread char *mysql_thread___keep_multiplexing_variables;
 __thread char *mysql_thread___init_connect;
 __thread char *mysql_thread___ldap_user_variable;
-__thread char *mysql_thread___default_tx_isolation;
 __thread char *mysql_thread___default_session_track_gtids;
 __thread char *mysql_thread___firewall_whitelist_errormsg;
 __thread int mysql_thread___max_allowed_packet;
@@ -947,7 +946,6 @@ extern __thread char *mysql_thread___server_version;
 extern __thread char *mysql_thread___keep_multiplexing_variables;
 extern __thread char *mysql_thread___init_connect;
 extern __thread char *mysql_thread___ldap_user_variable;
-extern __thread char *mysql_thread___default_tx_isolation;
 extern __thread char *mysql_thread___default_session_track_gtids;
 extern __thread char *mysql_thread___firewall_whitelist_errormsg;
 extern __thread int mysql_thread___max_allowed_packet;
diff --git a/lib/MySQL_Thread.cpp b/lib/MySQL_Thread.cpp
index 47d3169d0b..a7965a428d 100644
--- a/lib/MySQL_Thread.cpp
+++ b/lib/MySQL_Thread.cpp
@@ -423,7 +423,6 @@ static char * mysql_thread_variables_names[]= {
 	(char *)"init_connect",
 	(char *)"ldap_user_variable",
 	(char *)"add_ldap_user_comment",
-	(char *)"default_tx_isolation",
 	(char *)"default_session_track_gtids",
 	(char *)"connpoll_reset_queue_length",
 	(char *)"min_num_servers_lantency_awareness",
@@ -986,7 +985,6 @@ MySQL_Threads_Handler::MySQL_Threads_Handler() {
 	for (int i=0; i<SQL_NAME_LAST_LOW_WM; i++) {
 		variables.default_variables[i]=strdup(mysql_tracked_variables[i].default_value);
 	}
-	variables.default_tx_isolation=strdup((char *)MYSQL_DEFAULT_TX_ISOLATION);
 	variables.default_session_track_gtids=strdup((char *)MYSQL_DEFAULT_SESSION_TRACK_GTIDS);
 	variables.ping_interval_server_msec=10000;
 	variables.ping_timeout_server=200;
@@ -1248,12 +1246,6 @@ char * MySQL_Threads_Handler::get_variable_string(char *name) {
 				return strdup(variables.default_variables[i]);
 			}
 		}
-		if (!strcmp(name,"default_tx_isolation")) {
-			if (variables.default_tx_isolation==NULL) {
-				variables.default_tx_isolation=strdup((char *)MYSQL_DEFAULT_TX_ISOLATION);
-			}
-			return strdup(variables.default_tx_isolation);
-		}
 		if (!strcmp(name,"default_session_track_gtids")) {
 			if (variables.default_session_track_gtids==NULL) {
 				variables.default_session_track_gtids=strdup((char *)MYSQL_DEFAULT_SESSION_TRACK_GTIDS);
@@ -1369,12 +1361,6 @@ char * MySQL_Threads_Handler::get_variable(char *name) {	// this is the public f
 			return strdup(variables.add_ldap_user_comment);
 		}
 	}
-	if (!strcasecmp(name,"default_tx_isolation")) {
-		if (variables.default_tx_isolation==NULL) {
-			variables.default_tx_isolation=strdup((char *)MYSQL_DEFAULT_TX_ISOLATION);
-		}
-		return strdup(variables.default_tx_isolation);
-	}
 	if (!strcasecmp(name,"default_session_track_gtids")) {
 		if (variables.default_session_track_gtids==NULL) {
 			variables.default_session_track_gtids=strdup((char *)MYSQL_DEFAULT_SESSION_TRACK_GTIDS);
@@ -1704,19 +1690,6 @@ bool MySQL_Threads_Handler::set_variable(char *name, const char *value) {	// thi
 		return true;
 	}
 
-	if (!strcasecmp(name,"default_tx_isolation")) {
-		if (variables.default_tx_isolation) free(variables.default_tx_isolation);
-		variables.default_tx_isolation=NULL;
-		if (vallen) {
-			if (strcmp(value,"(null)"))
-				variables.default_tx_isolation=strdup(value);
-		}
-		if (variables.default_tx_isolation==NULL) {
-			variables.default_tx_isolation=strdup((char *)MYSQL_DEFAULT_TX_ISOLATION); // default
-		}
-		return true;
-	}
-
 	if (!strcasecmp(name,"default_session_track_gtids")) {
 		if (variables.default_session_track_gtids) free(variables.default_session_track_gtids);
 		variables.default_session_track_gtids=NULL;
@@ -2533,7 +2506,6 @@ MySQL_Threads_Handler::~MySQL_Threads_Handler() {
 	if (variables.init_connect) free(variables.init_connect);
 	if (variables.ldap_user_variable) free(variables.ldap_user_variable);
 	if (variables.add_ldap_user_comment) free(variables.add_ldap_user_comment);
-	if (variables.default_tx_isolation) free(variables.default_tx_isolation);
 	if (variables.default_session_track_gtids) free(variables.default_session_track_gtids);
 	if (variables.eventslog_filename) free(variables.eventslog_filename);
 	if (variables.auditlog_filename) free(variables.auditlog_filename);
@@ -2664,7 +2636,6 @@ MySQL_Thread::~MySQL_Thread() {
 	if (mysql_thread___init_connect) { free(mysql_thread___init_connect); mysql_thread___init_connect=NULL; }
 	if (mysql_thread___ldap_user_variable) { free(mysql_thread___ldap_user_variable); mysql_thread___ldap_user_variable=NULL; }
 	if (mysql_thread___add_ldap_user_comment) { free(mysql_thread___add_ldap_user_comment); mysql_thread___add_ldap_user_comment=NULL; }
-	if (mysql_thread___default_tx_isolation) { free(mysql_thread___default_tx_isolation); mysql_thread___default_tx_isolation=NULL; }
 	if (mysql_thread___default_session_track_gtids) { free(mysql_thread___default_session_track_gtids); mysql_thread___default_session_track_gtids=NULL; }
 
 	for (int i=0; i<SQL_NAME_LAST_LOW_WM; i++) {
@@ -3959,8 +3930,6 @@ void MySQL_Thread::refresh_variables() {
 	mysql_thread___ldap_user_variable=GloMTH->get_variable_string((char *)"ldap_user_variable");
 	if (mysql_thread___add_ldap_user_comment) free(mysql_thread___add_ldap_user_comment);
 	mysql_thread___add_ldap_user_comment=GloMTH->get_variable_string((char *)"add_ldap_user_comment");
-	if (mysql_thread___default_tx_isolation) free(mysql_thread___default_tx_isolation);
-	mysql_thread___default_tx_isolation=GloMTH->get_variable_string((char *)"default_tx_isolation");
 	if (mysql_thread___default_session_track_gtids) free(mysql_thread___default_session_track_gtids);
 	mysql_thread___default_session_track_gtids=GloMTH->get_variable_string((char *)"default_session_track_gtids");
 
diff --git a/test/tap/tests/proxysql_reference_select_config_file.cnf b/test/tap/tests/proxysql_reference_select_config_file.cnf
index b65de997b9..811fe356aa 100644
--- a/test/tap/tests/proxysql_reference_select_config_file.cnf
+++ b/test/tap/tests/proxysql_reference_select_config_file.cnf
@@ -117,7 +117,6 @@ mysql_variables =
 	default_sql_select_limit="mysql"
 	default_time_zone="mysql"
 	default_transaction_read="mysql"
-	default_tx_isolation="mysql"
 	default_wsrep_sync_wait="mysql"
 	enforce_autocommit_on_reads="mysql"
 	eventslog_default_log="mysql"
diff --git a/test/tap/tests/test_cluster_sync-t.cpp b/test/tap/tests/test_cluster_sync-t.cpp
index 6b79383cb4..253247b43d 100644
--- a/test/tap/tests/test_cluster_sync-t.cpp
+++ b/test/tap/tests/test_cluster_sync-t.cpp
@@ -2323,7 +2323,6 @@ int main(int, char**) {
 			std::make_tuple("mysql-init_connect"                                           , ""                           ),
 			std::make_tuple("mysql-ldap_user_variable"                                     , ""                           ),
 			std::make_tuple("mysql-add_ldap_user_comment"                                  , ""                           ),
-			std::make_tuple("mysql-default_tx_isolation"                                   , "READ-COMMITTED"             ),
 			std::make_tuple("mysql-default_session_track_gtids"                            , "OFF"                        ),
 			std::make_tuple("mysql-connpoll_reset_queue_length"                            , "50"                         ),
 			std::make_tuple("mysql-min_num_servers_lantency_awareness"                     , "1000"                       ),