The perceived benefits and risks of genetic testing may vary between groups of individuals with different cultural, demographic, and family history features. This multicentre study examined the factors that influenced the decision to undergo genetic testing for BRCA1 and BRCA2 in Canadian Jewish women with breast cancer. A self-administered questionnaire was developed and distributed to 134 individuals enrolled in a research-based testing program for Ashkenazi women. The questionnaire assessed demographic, social, and family history parameters, and the influence of medical, family, social, psychological, and cultural/religious factors on decision making about genetic testing. Seventy-six percent of women completed the questionnaire. Forty-one percent of study participants had no family history of breast or ovarian cancer. The most important factors influencing the decision to undergo testing were a desire to contribute to research, potential benefit to other family members, curiosity, and the potential for relief if not found to be a carrier (endorsed by 87, 78, 70, and 60% of participants, respectively). The main perceived risks of undergoing genetic testing related to insurance discrimination, confidentiality, accuracy and interpretability of results, potential impact on marriage prospects for family members, and focus on the Jewish community (endorsed by 28, 24, 30, 17, and 14% of participants, respectively). This study provides novel information on the motivating factors for BRCA1 and BRCA2 mutation testing in Canadian women of Ashkenazi Jewish descent. The focus on altruistic factors and those related to perceived psychological benefits of testing is notable.