The aim of this study was to determine general practice characteristics associated with testing rates for hepatitis C virus (HCV) and the proportion of tests with a positive result. The study included all patients tested for HCV from all general practices in the primary care trusts in Nottingham and Southern Derbyshire, UK over 2 years. There was a large variation between practices in HCV testing rates and the proportion of positive tests. Single-handed practices had higher testing rates and rates of positive results. Practices where at least half of the GPs were female had higher testing rates but lower positivity rates. The variation observed was not explained by deprivation or rurality of the practice.