A service catalog is a formal list of services offered by an organisation. It provides a clear and concise description of each service, including its purpose, capabilities, and the terms and conditions under which it is offered.

The service catalog is an important tool for service management because it helps to ensure that the services provided by the department meet the needs of the business and are delivered consistently and efficiently. It also helps to establish clear lines of communication and accountability.

The service catalog is typically organized into categories, with each category containing a list of services and their associated details. It may also include information about the service level agreements (SLAs) and service level objectives (SLOs) that apply to each service, as well as any related documentation or resources  

In ITIL4, the service catalog is part of the service portfolio management process.