The study reported in this article was undertaken in response to the participation of a general practice in the National Chlamydia Screening Programme (www.chlamydiascreening.nhs.uk). The aim of the study was to measure the extent of patient involvement in the programme and the differences in diagnosis rates and outcomes as a result. The article highlights the opportunities and challenges of delivering an existing service in the primary care setting and the effect of early diagnosis and treatment of chlamydia.