Introduces the concept of service level agreements (SLAs) in IT service provision, especially in the case of outsourced service provision. Reports the experience of several consulting engagements and surveys to substantiate suggested frameworks and checklists. Discusses the reasons for exercising rigour around SLAs. Differentiates between SLAs negotiated for internal versus external service providers. Describes the structure of good service level agreements. Outlines the most important elements of measurement for monitoring service level performance. Concludes with the importance of SLAs to the management of commercial relationships in which services are provided.