HIV prevalence is higher in jails than in the community, yet many jails do not conduct HIV testing. Jails in Baltimore, Maryland; Philadelphia, Pennsylvania; and the District of Columbia have implemented innovative rapid HIV testing programs. We have summarized the results of these programs, including the numbers of persons tested, rapid and confirmatory HIV test results, and numbers of persons newly diagnosed with HIV. We have described facilitators and challenges of implementation. These programs confirmed that rapid HIV testing in jails was feasible and identified undiagnosed HIV infection. Challenges included limited space to provide confidential rapid HIV testing and rapid turnover of detainees. Implementation required collaboration between local governments, health agencies, and correctional institutions. These programs serve as models for expanding rapid HIV testing in jails.