A service catalog (or catalogue), as defined in Information Technology Infrastructure Library Service Design, is an exhaustive list of IT services that an organization provides or offers to its employees or customers. The catalogue is the only part of the Service Portfolio that is published to customers and is used to support the sale and/or delivery of IT services. Each service within the catalog typically includes:
- A description of the service
- A categorization or service type
- Any supporting or underpinning services
- Timeframes or service level agreement for fulfilling the service
- Who is entitled to request/view the service
- Costs (if any)
- How to request the service and how its delivery is fulfilled
- Escalation points and key contacts
- Hours of service availability
A user's perspective
A user goes to a website to search for a specific service, such as requesting a new laptop, requesting a change in benefits, or adding a new employee to a department. The service catalog site groups services by category and allows for searching (especially when hundreds or thousands of services are available). The user selects a desired service and sees the description and details. The user enters any pertinent information (contact information, service-specific questions) and submits the request for service. The request requires approval, and goes through routing, service-level management, and other processes necessary to fulfill the request. The user may return to the site later to check on the status of a request, or to view overall metrics on how well the organization is performing the services it provides.
A business unit manager's perspective
Business Unit Managers determine what services to "publish" to end-users via the service catalog. Business Unit Managers and Analysts would determine what questions are to be asked of the user, any approvals necessary for a request, and what other systems or processes are needed to fulfill the request. Once the service is defined and the fulfillment process organized, these people or a more technical employee would build the requisite functionality into the service definition and then publish this to the service catalog.
Service catalogs for cloud computing services
The use of a service catalog for cloud computing services is an integral part of deploying services on private and public clouds. Users wishing to consume cloud services would use a cloud service catalog to view what cloud services are available, their function, and know the technologies used to provide the services. 
Users would also see the available different service level options based on latency and reliability. With this knowledge, users are able to change the configuration of the technologies used to deliver the services based on cost, performance and technology improvements.
By seeing and understanding the different services available through the cloud users can better appreciate what is available to them, compared to traditional IT whereby one group of users or business unit may be unaware of the technologies available to another unit. 
Accessed by self-service portals, service catalogs contain a list of cloud services from which cloud consumers select for self-provisioning of cloud services. This removes the need for users to work through various IT departments in order to provision a cloud service, nor are users required to provide detailed IT specifications. They are only required to provide business and organization requirements.
To make selection easier and to speed service deployment, service definitions are often standardized in cloud service catalogs. This presents three benefits: improved capacity planning, particularly if standard components are used; quicken service provisioning; and better buying forecasts which helps to lower costs.
Automation is an aspect of cloud service catalog that has been noted. Cloud service catalogs have been described as enabling "cloud on auto-pilot" enabling cloud users to build cloud services based on pre-built templates selected from catalogs.
- How to Produce An Actionable IT Service Catalog
- The Eight Essential Elements of an IT Service Lifecycle
- IT Governance
- Information Technology Infrastructure Library
- IT Service Management
- Service request management
DuMoulin, Fine, Flores. Defining IT Success through the IT Service Catalog, Van Haren Publishing. ISBN 978-90-77212-96-7
- Onisick, Joe. "Private cloud success factors include service catalog," Network Computing, January 05, 2012 
- Miller, Rich. "Cisco buys NewScale for cloud service catalogs," Datancenterknowledge.com, March 29, 2011 
- Flores, Rodrigo. "The competitive threat of public clouds," Datacenterknowledge.com, June 4, 2010.