Partner counseling and referral services (PCRS) are part of the spectrum of care for HIV-positive people and their sexual or needle-sharing partners. Referral includes notifying partners of exposure, after which they are (ideally) tested and receive prevention or risk reduction counseling or enter into care (if they test positive). Using The Guide to Community Preventive Services's methods for systematic reviews, the effectiveness of PCRS was evaluated, including partner notification, in identifying a population at high risk of HIV infection and in increasing testing in those populations. In this review, PCRS efforts using provider referral were found to be effective in reaching a population with a high prevalence of HIV. Nine studies qualified for the review. In these studies, a range of one to eight partners was identified per index case (a person newly diagnosed with HIV who has partners who should be notified); a mean of 67% of identified partners were found and notified of their potential exposure to HIV, and a mean of 63% of those notified were tested (previously known "positives" were not tested). Of those tested, a mean of 20% were HIV positive. Therefore, even given that not all partners could be found and notified and that some who could be found did not accept testing, 1% to 8% of people named as potentially exposed and not previously known to be HIV positive were identified as HIV positive through partner notification (although these people were not necessarily infected by the index case). Evidence was insufficient to determine whether PCRS, including partner notification, was also effective in changing behavior or reducing transmission because available studies did not generally report on these outcomes. Little empirical evidence was available to assess potential harm of the interventions, but current studies have not shown substantial harms. Based on Community Guide rules of evidence, sufficient evidence shows that PCRS with partner notification by a public health professional ("provider referral") effectively increases identification of a high-prevalence target population for HIV testing.