Between 1984 and 1987, 176 Norwegian patients with histologically verified unresectable pancreatic adenocarcinoma were randomized to double-blind treatment with oral tamoxifen (30 mg daily; 48 men and 44 women) or placebo (47 men and 37 women). Analysis of oestrogen receptor activity in the carcinomas was not performed. There were no statistically significant differences between the two groups according to age, Karnofsky performance index, tumour node metastasis (TNM) stage, operative treatment or other patient characteristics. The tamoxifen or placebo treatment continued to death or to 10 months after accrual into the trial was stopped. In the tamoxifen group, the mean and median survivals were 205 and 115 days, respectively. These values did not differ statistically from the 192 and 122 days, respectively, observed in the placebo group. Additional retrospective analyses of sex and stage revealed no beneficial effect of tamoxifen upon survival. For women in stage III (any T N1 M0), mean and median survivals were 255 and 191 days, respectively, compared with values of 84 and 45 days, respectively, in the placebo group (P = 0.011). After 2.5 years, three (7 per cent) women in the tamoxifen group were still alive compared with no survivors in the placebo group. No male patients survived beyond 2.5 years. This therapeutic result in a small subgroup of women is probably incidental and not an effect of tamoxifen.