A total of 271 inmates out of the original sample of 5,265 tested positive for HIV/AIDS; 33 of these 271 inmates were determined to have contracted HIV while in prison, and 238 were diagnosed with HIV/AIDS after leaving prison. Four variables had a statistically significant association with having contracted HIV inside prison: age as of January 1, 1978; being non-White; having been convicted of a sexual crime; and the number of days spent in prison before being released for the first time or January 1, 2000, which ever came first. Each year an inmate was older decreased the chance that he would contract HIV in prison by 1.09 times. Modeling the types of inmates at risk for contracting HIV in prison can help policymakers improve current prevention practices. The study first obtained a dataset that contained information on all male inmates in the State prison system on January 1, 1978. This date is significant, because HIV and AIDS were not identified in the U.S. population before 1978. Researchers accessed the State HIV/AIDS Reporting System dataset to obtain information on all persons in the State who had HIV or AIDS. Datasets were cross-matched using the name, race, birth date, and social security number, which identified those persons in the inmate dataset who were known to have HIV/AIDS. The date of HIV/AIDS diagnosis for each matched case was imported into the inmate dataset. Inmates who contracted HIV inside prison were identified by the staff of the State Department of Health. 3 tables and 57 references