A C to T transition within the 3' untranslated region of the prohibitin gene alters mRNA function, and an association between the T allele and an increased risk of breast cancer has been reported in North American women, specifically in those aged under 50 years with a first-degree family history of breast cancer. We did a population-based case-control study to assess whether this association existed in Australian women. We did not note such an association in our sample of 1446 patients and 786 controls (odds ratio 0.96, 95% CI 0.80-1.16; p=0.7), or in subgroups defined by age or family history, or both. Hence, our results do not lend support to the hypothesis that this polymorphism contributes to risk of breast cancer.