Adolescents are particularly vulnerable to HIV and account for one quarter of all new infections each year. Most new infections (72%) among adolescents occur among young men who have sex with men (YMSM). Transmission of HIV can be virtually eliminated by treatment, but testing rates are low and a significant proportion of YMSM are unaware of their HIV status. Perceived and actual stigma and discrimination may prevent these young men from engaging in health systems and very few programs have been designed to effectively promote testing among YMSM. This Phase I project will create a theory-based (Information, Motivation, and Behavioral Skills model), serious mobile game to promote HIV testing among YMSM living on the South and West sides of Chicago. Communities comprised predominately of African American and Latino communities. Three specific aims will be completed over a six-month period: (1) Develop the Test prototype with a stakeholder advisory team; (2) Conduct prototype usability, feasibility, and acceptability testing with youth and providers; and (3) prepare for Phase II full development. The Test will directly address the need for innovative solutions to low rates of HIV testing among YMSM using a state-of-the-art, theory-based video game designed specifically for YMSM. This game will engage YMSM in self- paced, developmentally appropriate, interactive instruction and practice to enhance their information, motivation, and behavioral skills with regards HIV testing.