A national audit was performed to ascertain details of the management of clinically obese women at infertility clinics in the UK. This was with particular reference to body mass index (BMI) limits for specific treatments and general advice given to patients regarding obesity. A postal questionnaire was sent to all licensed assisted conception units (ACUs) in the UK offering fertility treatment. The return rate was 86 of 100 (86%). There was a great deal of variation between different units in the practice standards of obese infertile women. This audit demonstrates the wide variation in current UK practice and highlights the need for a broad discussion and adoption of national guidelines for the management of obese infertile women.