We investigated the prognostic significance of mutation to the TP53 tumor suppressor gene in a series of 908 breast cancer patients treated with or without adjuvant therapies. The frequency of TP53 mutation detected by single strand conformation polymorphism (SSCP) was 19.4% (176/908) in the overall tumor series. In multivariate analysis, TP53 mutation was independently associated with worse survival in the overall (HR = 2.1, 95% CI [1.5-3.1], P<0.0001), non-adjuvant treated (HR=2.2, 95% CI [1.2-4.2], P=0.017) and adjuvant treated (HR= 2.0, 95% CI [1.3-3.1], P = 0.0009) patients.