Adjuvant chemotherapy for early breast cancer improves survival but is unpleasant and inconvenient. Women and clinicians need information about the magnitude of survival benefits considered sufficient to make the side-effects and inconvenience worthwhile. We sought studies that quantified the minimum required survival benefit by asking women who had experienced adjuvant chemotherapy. Four studies involving 512 women were appraised and summarised. All studies referred to chemotherapy given between 1980 and 1996, but the methods varied widely, especially the way in which women were recruited and questioned. However, the results were remarkably consistent. Most women said that small improvements in survival were sufficient to make adjuvant chemotherapy worthwhile. Women with dependants, social support, and milder side-effects judged smaller benefits worthwhile. Age, education, employment, and income status were not predictive of the women's responses. Optimum decision-making about the relative benefit of adjuvant chemotherapy requires up-to-date information from women receiving current chemotherapy and supportive regimens.