370 patients with operable, axillary node positive breast cancer, were randomized to receive tamoxifen (TAM) 20 mg/day for 2 years or no adjuvant hormone therapy. All patients had estrogen receptor (ER) positive (ER > 10 pmol/g) primary tumours. 350 patients, 93 younger than 50 years of age and 257 patients 50 years or older, were evaluable for the study. After a median follow up of 76 months, significantly (p = 0.0001) fewer loco-regional, but not distant (systemic), relapses have been recorded in the TAM group. Overall survival was also improved, but even though the study was designed to give maximum benefit from TAM statistically significant effect of TAM seemed to be limited to patients 50 years of age and older.