Our goal was to identify the treatment, personal, interpersonal, and hormonal (testosterone) factors in breast cancer survivors (BCSs) that determine sexual dysfunction. The treatment variables studied were type of surgery, chemotherapy, radiation, and tamoxifen. The personal, interpersonal, and physiologic factors were depression, body image, age, relationship distress, and testosterone levels. A sample of 55 female breast cancer survivors seen for routine follow-up appointments from July 2002 to September 2002 were recruited to complete the Female Sexual Functioning Index (FSFI), Hamilton Depression Inventory (HDI), Body Image Survey (BIS), Marital Satisfaction Inventory-Revised (MSI-R), a demographic questionnaire, and have a serum testosterone level drawn. The average time since diagnosis was 4.4 years (SD 3.4 years). No associations were found between the type of cancer treatment, hormonal levels, and sexual functioning. BCS sexual functioning was significantly poorer than published normal controls in all areas but desire. The BCSs’ level of relationship distress was the most significant variable affecting arousal, orgasm, lubrication, satisfaction, and sexual pain. Depression and having traditional role preferences were the most important determinants of lower sexual desire. BCSs on antidepressants had higher levels of arousal and orgasm dysfunction. Women who were older had significantly more concerns about vaginal lubrication and pain. Relationship concerns, depression, and age are important influences in the development of BCS sexual dysfunction. The relationship of testosterone and sexual dysfunction needs further study with larger samples and more accurate assay techniques.