Focal nodular hyperplasia of the liver was found in 3 women, and liver cell adenoma in a 4th woman. There is a possible association with the use of oral contraceptives. The indication for operation in these cases depends on the size of the tumour (danger of rupture of tumour and haemorrhage). It is also present when a malignant tumour cannot be excluded. Resection of the liver was performed predominantly with good results so far. Three of the patients described underwent the same surgical procedure. For the future one should aim at tumour enucleation alone.