: HIV Infection resulting in AIDS remains serious global public health problem. In the fight with the global health problem plays a key role a simple, reliable and fast diagnostics. An important method in diagnostics is the identification and detection of viral capside p24 antigen levels. Fourth generation tests for the diagnostics of HIV infection simultaneously detect the presence of HIV antibodies and p24 antigen. Based on the monitoring of CD4 count, we can estimate the stage in which the infection is, and we can also suggest a therapeutic approach. Cerebral toxoplasmosis is the most common neurological opportunistic disease manifested in HIV infected patients. Cryptococcal meningitis is the second most common cause of the opportunistic neuroinfections. Despite of significant advances in the diagnostics and treatment of HIV infection, this disease is still unable to get completely under control. The future perspective in HIV diagnostics are biosensors.