HIV testing plays a crucial role in detecting and monitoring HIV infection. Diagnosis of HIV infection is basically made by sequential two tests: a screening test with an enzyme immunoassay(EIA) and a confirmatory test with Western blot. The most recent EIAs, used in commercial laboratories, identify HIV infection earlier because they detect both HIV-1 antibody and antigen. Rapid tests represent another advance for HIV screening. They are widely used in voluntary counselling and testing at public health centers and private clinics. An assay for detection of HIV-1 RNA was approved as a confirmatory test of reactive screening tests to diagnose early infection. These new testing technologies offer more accurate, reliable, and convenient diagnosis of HIV infection.