PURPOSE: The purpose of the present study was to examine whether women who seek genetic counselling for Hereditary Breast and Ovarian Cancer (HBOC), assess their own risk different when they compare it to either (a) an average woman in the general population, or (b) another woman also seeking genetic counselling. In addition, we explored some medical and psychological factors related to these women's comparative risk assessment. METHODS: Before counselling, 620 women filled out a first questionnaire assessing their comparative risk estimates. RESULTS: Results showed that these women consider their risk higher than that of a woman from the general population (i.e., a pessimistic response), but equal to the risk of another counselee. The latter comparative risk measure was also more normally distributed implying that comparing to a similar other person is a more relevant comparison. Women were more pessimistic comparing to another counselee if they had had breast cancer, and more optimistic if they had no first-degree relatives with breast cancer, perceived a low absolute risk, and had stronger dispositional optimistic tendencies. Additional analyses showed that affective perceived absolute risk outperformed worry as well as a numerical perceived absolute risk as a predictor of perceived risk relative to another counselee. CONCLUSIONS: Overall, women who sought genetic counselling for breast cancer had unbiased comparative risk perceptions and correctly assessed their own risk status. In addition, it seems that affective risk perception both encompasses an aspect of cognitive probability and an aspect of emotional fear.