Genetic testing enables women at risk for hereditary breast and/or ovarian cancer to find out whether they have inherited the gene mutation (BRCA1/BRCA2), and if so, to opt for frequent surveillance and/or prophylactic surgery (bilateral mastectomy and/or oophorectomy). Here, a follow-up is described for 63 healthy women at 50% risk of being a BRCA1/BRCA2 mutation carrier who underwent genetic testing. The course of distress and problems regarding body image and sexuality up to 1 year after disclosure of the test-outcome were described separately for mutation carriers undergoing mastectomy (n = 14), for mutation carriers opting for surveillance (n = 12) and for non-mutation carriers (n = 37). Furthermore, we analyzed whether women opting for prophylactic mastectomy differed from those opting for close surveillance with respect to biographical characteristics, experiences with cancer in relatives and personality. Women opting for prophylactic mastectomy had significantly higher distress levels than mutation carriers who opted for surveillance, and the non-mutation carriers. This difference in levels of distress was highest at pre- and post-test and had almost disappeared at 1-year follow-up. Besides, mutation carriers opting for prophylactic mastectomy were more often in their thirties, more often had young children and had a longer awareness of the genetic nature of cancer in the family than those opting for regular surveillance. Adverse effects were observed in women who underwent prophylactic mastectomy (mostly in combination with immediate breast reconstruction) regarding the perception of how their breast region looked like and felt, the intimate relationship and physical wellbeing whereas women opting for prophylactic mastectomy reported more distress than the other women in the study, their distress levels had significantly decreased 6 months or longer after surgery, possibly due to the significant risk reduction of developing breast cancer. This might explain, why most women who underwent prophylactic mastectomy were satisfied with this decision, despite a perceived negative impact on body image, the intimate relationship and physical wellbeing.