37 cases of extragenital tumours metastatic to the ovaries are analysed from a clinicopathological viewpoint. In 25 out of 334 patients who were operated on between 1978 and 1990 because of a palpable malignant ovarian tumour, ovarian involvement from extragenital cancer was diagnosed. The most frequent primary sites were the stomach (n = 7), colon (n = 6) and breast (n = 6). 4 of the 6 patients with metastatic colon carcinoma had previously documented diagnosis of colon cancer with a time interval between diagnosis of primary tumours and secondary ovarian tumour ranging up to 11 years. Only one patient had a previously known stomach cancer, operated on 32 months earlier. All our patients with gastrointestinal primary tumour died within 1 year (gastric origin) of detection of metastases and 2 years (colon carcinoma) except for one patient with metastasis of colon carcinoma, who is still living after more than 4 years and one patient with gastric carcinoma who survived 34 months after oophorectomy. Surprisingly, ovarian metastases of breast cancer were detected before the primary tumour in 2 out of 6 cases. The other 4 patients were operated on because of an ovarian tumour but had a known and previously operated breast cancer. 27 patients had therapeutic ovarian ablation in metastatic breast cancer without a palpable pelvic mass. None of these patients had symptoms related to the ovaries. In 12 (40%) patients we found microscopic metastases which were bilateral in 9 cases. Metastases to the ovary may not infrequently mimic primary ovarian tumour and are difficult to diagnose preoperatively. We hope that some clinical features described by us (nationality, patient's history, bilateral ovarian tumours in young women) will alert the clinician to investigate further in order to achieve the best possible therapeutic management, because some patients may benefit from adequate treatment and survive for a long time.