We report the results of the first study designed to evaluate the feasibility and acceptability of an HIV prevention intervention focused on concurrent sexual partnerships. Mathematical models and longitudinal studies of stable couples indicate concurrency plays a critical role in sustaining generalized HIV epidemics in heterosexual populations, and East and Southern African nations identified concurrency reduction as a priority for HIV prevention. "Know Your Network" (KYN) is a single-session community-level concurrency awareness intervention designed to address this need. It is rooted in traditional social network research, but takes advantage of new network methodology and years of participatory action research with communities living in a region of Kenya with the highest HIV prevalence nationally. KYN combines didactic presentation, interactive exercises, high-impact graphics, and a network survey with immediate visualization of the results, to prompt a community conversation about sexual norms. We combined focus group discussions and the traditional east African baraza to evaluate the feasibility and acceptability of KYN for use with adults living in rural Nyanza Province, Kenya. We were able to implement KYN with fidelity to its components. Participants understood the intervention's messages about concurrency and its role in HIV transmission through sexual networks. They agreed to provide anonymous egocentric data on their sexual partnerships, and in return we successfully simulated a representation of their local network for them to view and discuss. This launched a dynamic conversation about concurrency and sexual norms that persisted after the intervention. The concurrency message was novel, but resonant to participants, who reported sharing it with their children, friends, and sexual partners. With clear evidence of KYN's feasibility and acceptability, it would be appropriate to evaluate the effectiveness of the intervention using a community-randomized trial. If effective, KYN would offer an inexpensive complement to ongoing comprehensive HIV prevention efforts in generalized epidemic settings.