OBJECTIVE Adult patients with Turner's syndrome are rarely followed up at specialist clinics after discharge from paediatric care but do have a predisposition to several long‐term medical problems. We have assessed the undiagnosed morbidity that exists among adult women with Turner's syndrome.PATIENTS A group of 32 women (age range 17–52 years; mean 25 years) attending a specialist out‐patient clinic.MEASUREMENTS Blood samples were obtained at the initial visit for lipid assessment, thyroid function, gonadal status and routine biochemical profile. Bone mineral density (BMD) was measured in 31 of the women.RESULTS Thirty‐one women were receiving some form of oestrogen replacement. Two were receiving T4 therapy. In 50%, total cholesterol was greater than 5.2 mmol/l (range 3.4–9.3 mmol/l, mean 5.8 mmol/l) and 28% had an abnormality of thyroid function tests. Two women were newly diagnosed as hypothyroid, 6 had compensated hypothyroidism and one was under‐replaced with T4. Lumbar spine BMD was below 100% of age matched reference range in 84% and below 75% in 26% of patients. Femoral neck BMD was below 100% of age matched reference range in 90% and below 75% in 10% of patients.CONCLUSIONS There is a high incidence of undiagnosed lipid, thyroid and bone mineral density abnormalities in the adult population with Turner's syndrome. Doctors caring for these women need to be aware of and look for the potential problems. Appropriate long‐term treatment should be commenced to help prevent the development of lipid, skeletal and thyroid abnormalities which may cause these patients