Findings from the study indicate important associations between both sociodemographic and arrest-related factors and HIV infection. HIV prevalence was higher in males than females and highest in African-Americans, followed by Whites among both male and female inmates. Male and female parole violators, males arrested for sex or theft charges, and females arrested for drug or violent charges were more likely to have undiagnosed HIV infections than males and females arrested for other reasons. The data provided preliminary evidence that, in jail settings where universal routine screening is not feasible, selective screening for HIV based on arrest should be further explored as a strategy for identifying undiagnosed infections. Despite high documented HIV prevalence, few jail systems offer universal HIV screening, nor is this always feasible. This study evaluated undiagnosed HIV infection and HIV risk history by arrest charge among 1,322 new arrestees within 2 facilities of the Los Angeles County Sheriff’s Department to examine whether specific charges might help prioritize jail-based screening. Tables and references