The authors investigated the association between the reported frequency of breast self-examination and five dimensions of social support (material, emotional, affective, information, and positive social interaction) among 2,240 female employees from a university in Rio de Janeiro who were participants in Phase 1 of a cohort study (Pró-Saúde Study). Data were collected through a multidimensional self-administered questionnaire. Among participants, 43% reported doing breast self-examination "every month", or "almost every month"; 24% informed they seldom or never practiced self-examination. Participants with the highest scores in the five dimensions of social support reported higher frequency of breast self-examination. In all dimensions, the odds of practicing self-examination were approximately twice as high among women in the upper tertile of social support scores and about 50% higher among those in the intermediate tertile, as compared to those in the lower tertile of the scores (linear trend test, p < 0.001). The results' consistency suggests that several dimensions of social support can contribute positively to the regular practice of health-related self-care.