SYNOPSISObjectives. Partner counseling and referral services (PCRS) provide a unique opportunity to decrease transmission of human immunodeficiency virus (HIV) by notifying sex and drug-injection partners of HIV-infected individuals of their exposure to HIV. We incorporated rapid HIV testing into PCRS to reduce barriers associated with conventional HIV testing and identify undiagnosed HIV infection within this high-risk population. Results. A total of 2,678 index clients were identified, of whom 779 (29%) provided partner locating information. A total of 1,048 partners were elicited, of whom 463 (44%) were both interviewed and tested for HIV. Thirty-seven partners (8%) were newly diagnosed with HIV. The number of index clients interviewed to identify one partner with newly diagnosed HIV infection ranged from 10 to 137 at the participating sites.