Since 2006, CDC has recommended routine, opt-out human immunodeficiency virus (HIV) screening for patients in health-care settings with a prevalence of undiagnosed HIV infection of ≥0.1%. Before September 2007, the Washington State Department of Corrections (WADOC) only provided HIV testing to inmates on request. In September 2007, WADOC began routine HIV opt-in screening in which inmates were notified that HIV screening would be performed during the prison intake medical evaluation if they consented. In March 2010, WADOC switched to a routine opt-out HIV screening model in which inmates are notified that HIV screening will be performed unless they decline. To assess the proportion of inmates screened and the number of infections diagnosed during the use of the three HIV testing policies, WADOC reviewed HIV testing data for male inmates undergoing intake medical evaluation during January 2006–December 2010.