Patient records in general practice surgeries are a unique resource that can provide evidence to help medical researchers improve their understanding of disease, develop potential new treatments and improve patient care. But patient information is both sensitive and private, and the security of personal data must be safeguarded. There is considerable uncertainty about the processes that should be used when information from patient records is required for research. The best practice guidance described in this document was developed during a national consensus meeting held at the Wellcome Trust in 2008 with GPs, researchers and patient groups. It is intended as the first step in a process to ensure that patients and GPs have confidence in the processes used to access patient information.