Aim: Patients with gynecologic cancer frequently experience bone loss due to cancer treatments, including bilateral oophorectomy, chemotherapy and radiotherapy. This study evaluated treatment-associated changes in bone mineral density (BMD) in women with gynecologic cancer and compared changes among patients with different types of gynecologic cancer. Methods: BMD of the lumbar spine and femur was retrospectively analyzed using dual-energy X-ray absorptiometry in 118 women who underwent treatment for gynecological cancers and 132 women without gynecologic cancers. The cohort included 55 women with cervical cancer who underwent surgery followed by adjuvant chemotherapy and/or radiation therapy, 33 with endometrial cancer (EC) who underwent surgery followed by adjuvant radiation therapy and 30 with ovarian cancer who underwent bilateral oophorectomy followed by adjuvant platinum-based chemotherapy. Lumbar spine and femoral neck BMD were assessed at baseline and 12 months after treatment. Areal BMD, expressed as grams of mineral/cm2 scanned, was compared with that in young healthy women (T-score). Results: Demographic characteristics and pretreatment BMDs, including T-scores, did not differ among cancer types. After adjustment for factors that can affect T-score, cancer type affected change in T-score 12 months after treatment. After adjustment for pretreatment age, parity, BMI and T-score, T-score 12 months after treatment was significantly lower in the EC than in the other groups. Conclusions: Women treated for gynecological cancer, particularly those with EC who undergo bilateral oophorectomy followed by adjuvant radiation therapy or chemotherapy, should be managed in a timely manner to prevent or minimize bone loss.