This guideline covers diagnosing and treating fertility problems. It aims to reduce variation in practice and improve the way fertility problems are investigated and managed. The Royal College of Obstetricians and Gynaecologists has produced guidance for gynaecological services during the COVID-19 pandemic. In September 2017, we stood down section 1.7 in this guideline as it has been superseded by publication of the NICE guideline on endometriosis.