Gil-Llario MD, et al. - In this work, the AIDS Prevention Questionnaire (CPS), a brief HIV risk assessment measure, was built and validated. Four hundred and sixty-six young people (192 men and 274 women), aged between 17 and 26 years, were made to fill an initial 64-items bank. Five components were recognized in the exploratory factor analysis: Knowledge about HIV, Condom Attitudes, Intentions of Condom Use, Safe sexual behavior and Stigma and discrimination towards people living with HIV. Outcomes support that the AIDS Prevention Questionnaire is a valid and reliable measure to detect the earlier risk for HIV infection and to design adjusted preventive interventions.