A 65 year old woman presented with an ovarian mass. Ultrasonography and computed tomography findings, and an increased serum oestrogen concentration were suggestive of an oestrogen producing ovarian tumour. The tumour was removed surgically and weighed 460 g. The pathological diagnosis was adult-type granulosa cell tumour. Strong immunohistochemical staining specific for type IV collagen and laminin was observed, and these components were localised to the pericellular region of the granulosa cells. The serum concentrations of these basement membrane components (measured by radioimmunoassay) were very high before surgery, but decreased rapidly thereafter. Serial measurement of type IV collagen and laminin, in conjunction with other tumour markers and oestrogen concentrations, might be helpful in evaluating prognosis of ovarian granulosa cell tumours, in detecting metastatic or recurrent lesions and in monitoring response to treatment.