Background: Significant differences exist in the immunological response to surgery. This raises the possibility that gender differences exist concerning the outcome after curative colorectal cancer resection. Methods: To study this hypothesis, a database of patients with colorectal cancer was analysed prospectively. Results: Some 894 patients were included, 500 (55.9 per cent) were men and 394 (44.1 per cent) were women. Median follow-up was 54.5 months for the entire group and 63.3 months for survivors. The mean(s.e.m.) patient age was 65.3(0.4) years (women 66.1(0.6), men 64.7(0.5) years; P < 0.05). Women lived significantly longer after cancer resection than men (57.8(1.5) versus 52.0(1.3) months; P < 0.05, log rank 0.009). Disease-free survival was significantly longer in women than in men (51.6(1.7) versus 46.0(1.4) months; P < 0.05). Subgroup analysis revealed significant gender differences in Union Internacional Contra la Cancrum (UICC) stages I (n = 195, log rank 0.01) and UICC IV (n = 38, log rank 0.021). Survival analysis after rectal cancer resection revealed significant advantages for women (log rank 0.02), while no gender differences were detected when comparing patients after resection for colonic cancer. Moreover, patients older than 50 years (n = 635) showed significant gender-related survival differences (log rank 0.015). Conclusion: Significant gender differences following curative rectal cancer resection were observed. In women disease-free and overall survival were significantly longer. Whether or not these gender differences are related to gender-specific immune functions or to other gender-related local or systemic factors remains to be determined.