Copyright © 2014 American Sexually Transmitted Diseases Association All rights reserved. Background: African American women who have sex with women (WSW) are emerging as a population at risk for sexually transmitted infections (STIs). The objectives of this study were to explore partnership characteristics for a cohort of African American WSW and evaluate those characteristics as potential risk factors for STIs. In addition, we aimed to determine STI diagnoses and identify predictors of STI infection.Methods: Women who have sex with women presenting to a sexually transmitted disease clinic in Birmingham, AL, completed a questionnaire and were tested for bacterial vaginosis, trichomoniasis, chlamydia, gonorrhea, Mycoplasma genitalium, syphilis, HIV, and herpes simplex virus type 2.Results: A total of 163 women were enrolled: 78 WSW and 85 women who have sex with women and men (WSWM) (based on report of past year sexual behavior). Both WSWand WSWM reported similar numbers of female partners over the lifetime, past year, and past month; however, WSWM reported significantly more lifetime male partners, thus having a higher overall number of sexual partners. Women who have sex with women and men were more likely to report new or casual partner(s), group sex, history of STIs, and sex with partner(s) known to have STIs. Overall, WSWM were more likely to have a current diagnosis of bacterial vaginosis, a current diagnosis of a curable STI, or a diagnosis of a noncurable STI (85% vs. 56%, P < 0.01).Conclusions: African American WSW are not a homogeneous group, and their sexual health may be directly or indirectly influenced by male partners. A better understanding of the distinctions and differences between African American WSW and WSWM will enable health care providers to improve the quality of care provided.