The number of concurrent instant messaging sessions at a given time is limited. A user may configure the number of instant messaging sessions that are allowed at a given time. When a new request for an instant messaging session is received, a determination is made as to whether there are already the maximum number of allowed sessions. If the maximum number of sessions has been reached, the requestor receives a message indicating that the user is currently busy with other instant messaging sessions and inviting the requestor to join the queue. If the requestor joins the queue, then the requestor moves up in the queue when one of the user's instant messaging sessions terminate.