SUMMARYIn two adult patients with congenital poikiloderma (Rothmund‐Thomson syndrome) the following endocrine abnormalities were found: Patient 1, female, with short stature had primary amenorrhoea and did not develop secondary sexual characteristics. Despite lacking an oestrogen effect on the vaginal smear and the low urinary oestrogen excretion, basal LH and FSH and their response to LH‐RH were normal. At age 36 a parathyroid adenoma was diagnosed because of increased immunoreactive plasma parathyroid hormone and persistent hypercalcaemia. After removal of the tumour the patient remained normocalcaemic. The result of growth hormone response to insulin in the intermediate range was suggestive of partial deficiency. In patient 2, male, hypergonadotropic hypogonadism with small testes and high basal LH and FSH levels as well as increased LH and FSH response to LH‐RH were found. Plasma testosterone was normal. Endocrine abnormalities in previously published cases are summa