diff --git a/alerts.php b/alerts.php
index af7c83506..878c23e32 100755
--- a/alerts.php
+++ b/alerts.php
@@ -25,11 +25,29 @@
 
 include("includes/defaults.inc.php");
 include("config.php");
+
+$lock = false;
+if( file_exists($config['install_dir']."/.alerts.lock") ) {
+	$pids = explode("\n", trim(`ps -e | grep php | awk '{print $1}'`));
+	$lpid = trim(file_get_contents($config['install_dir']."/.alerts.lock"));
+	if( in_array($lpid,$pids) ) {
+		$lock = true;
+	}
+}
+
+if( $lock === true ) {
+	exit('Alreading running with PID '.$lpid."\r\n");
+} else {
+	file_put_contents($config['install_dir']."/.alerts.lock", getmypid());
+}
+
 include("includes/definitions.inc.php");
 include("includes/functions.php");
 
 RunAlerts();
 
+unlink($config['install_dir']."/.alerts.lock");
+
 /**
  * Run all alerts
  * @return void
diff --git a/librenms.cron b/librenms.cron
index f2171210f..49f74898d 100644
--- a/librenms.cron
+++ b/librenms.cron
@@ -2,4 +2,4 @@
 */5  *    * * *   root    /opt/librenms/discovery.php -h new >> /dev/null 2>&1
 */5  *    * * *   root    /opt/librenms/poller-wrapper.py 16 >> /dev/null 2>&1
 15   0    * * *   root    sh /opt/librenms/daily.sh >> /dev/null 2>&1
-*/2  *    * * *   root    /opt/librenms/alerts.php >> /dev/null 2>&1
+*    *    * * *   root    /opt/librenms/alerts.php >> /dev/null 2>&1