Objective To develop a method of collecting, organizing, and analyzing information on nutrient and nonnutrient dietary supplement use by women at risk for breast cancer recurrence as a component of nutrition assessment and monitoring, and to describe the characteristics associated with dietary supplement use in this population at enrollment in a clinical trial to prevent breast cancer recurrence.Design Cross-sectional descriptive study design.Subjects Women diagnosed with breast cancer within the previous 4 years (n=435).Analysis Dietary supplements reported in four 24-hour dietary recalls were categorized according to primary nutrient and nonnutrient contents. Prevalence of dietary supplement use is described. Associations between supplement use and demographic and participant characteristics were examined using χ 2 analysis and logistic regression.Results Dietary supplement use was reported by 80.9% of the women. Increased likelihood of supplement use was associated with demographic (eg, older age, higher level of education, white race vs other ethnic groups) and personal (eg, lower body mass index, moderate alcohol consumption) characteristics. Use of vitamin C and related compounds, other nutrients (eg, n-3 fatty acids, evening primrose oil), and herbal products was inversely associated with months since diagnosis; use of miscellaneous supplements (eg, shark cartilage) was directly associated with more advanced stage at diagnosis.Applications Monitoring dietary supplement use is an important aspect of nutrition assessment, especially in populations with chronic health conditions or medical diagnoses. Demographic and personal characteristics, time passed since diagnosis, and stage of cancer at diagnosis are predictive of dietary supplement use by women at risk for breast cancer recurrence. Associations in this population may be present in other groups that are the object of nutrition intervention efforts. J Am Diet Assoc. 1998;98:285-292.