Provided are messenger notification system and method using a synchronization server. The system includes a messenger service system controlling transmission of instant messages of messenger users and monitoring and transmitting messenger users' status change information; at least one external service system monitoring whether a predetermined event occurs and creating a notification message indicating the occurrence of the event when the event occurs; and a synchronization server receiving the messenger users' status change information from the messenger service system, storing the received status change information in an online user database, determining whether a user to receive the notification message is online when receiving the notification message from the at least one external service system, transmitting the notification message to the messenger service system to send the notification message to the online user when the user is online.