A computer implemented method, data processing system, and computer program product for automatically initiating an instant messaging (IM) chat session based on a calendar entry. A user's IM client receives instructions to initiate an IM chat session based on a scheduled entry in the calendaring system. These instructions may be received from the user's calendaring system or a continuously running service, such as a daemon, independent of the IM client. Upon receiving the instructions, the IM client may optionally alert the user to the impending chat session. The IM client then presents a chat window for the instant messaging chat session to the user at a time specified in the scheduled entry. Data associated with the scheduled entry in the calendaring system, such as notes or attachments related to the chat session, may also be displayed in the chat window.