A total of 254 patients with stages T1-3a/N0-1/M0 operable breast cancer were randomized to either surgery alone or surgery plus adjuvant chemoimmunotherapy (LMF + BCG). Ten-year results are presented for RFS (relapse-free survival) and OAS (overall survival) in the whole patient population as well as in the most important menopausal and nodal subgroups. LMF + BCG significantly increased RFS in the whole patient population as well as in node-positive women. The earlier impressive RFS and OAS gains for node-negative patients were fading after 5 and 8 years respectively, leaving marginal trends in favour of the LMF + BCG treated women. Node-positive patients treated with LMF + BCG continue to demonstrate a marginal gain in RFS up to 10 years. This gain is nearly exclusively expressed in postmenopausal node-positive women, an observation which can be made in the node-negative patient group as well. Despite the still continuing increase in RFS,' no OAS benefit was observed for node-positive women with LMF + BCG at any time of the study. Dose still remains a critical factor in cancer therapy. However, at 10 years of follow-up, a full dose of LMF (greater than or equal to 90%) during the six cycles no longer affects OAS favourably. There was no indication of any adverse long-term toxicity of LMF + BCG in our study after a median follow-up of 10 years, especially no increase of second tumours. In the node-negative patient population, the presence or absence of intramammary lymphatic infiltration seems to be a significant prognostic factor within this nodal subgroup.