BACKGROUND: Women with estrogen deficiencies can suffer from vaginal symptoms that negatively impact sexual health. This study evaluated vaginal dehydroepiandrosterone (DHEA) for alleviation of vaginal symptoms. METHODS: This three-arm randomized, controlled trial evaluated DHEA 3.25 mg and DHEA 6.5 mg, each compared to a plain moisturizer (PM) over 12 weeks, to improve the severity of vaginal dryness or dyspareunia, measured with an ordinal scale, and overall sexual health using the Female Sexual Function Index (FSFI). Postmenopausal women with a history of breast or gynecologic cancer who had completed primary treatment, had no evidence of disease, and reported at least moderate vaginal symptoms were eligible. The mean change from baseline to week 12 in the severity of vaginal dryness or dyspareunia for each DHEA dose was compared to PM and analyzed by two independent t tests using a Bonferroni correction. RESULTS: Four hundred sixty-four women were randomized. All arms reported improvement in either dryness or dyspareunia. Neither DHEA dose was statistically significantly different from PM at 12 weeks (6.25 mg, p = .08; 3.25 mg, p = 0.48), although a significant difference at 8 weeks for 6.5 mg DHEA was observed (p = 0.005). Women on the 6.5 mg arm of DHEA reported significantly better sexual health on the FSFI (p < 0.001). There were no significant differences in provider-graded toxicities and few significant differences in self-reported side effects. CONCLUSION: PM and DHEA improved vaginal symptoms at 12 weeks. However, vaginal DHEA, 6.5 mg, significantly improved sexual health. Vaginal DHEA warrants further investigation in women with a history of cancer.