Collecting data on maintaining anti-retroviral activity (quantitative HIV RNA determination) and immunological activity (CD4 cells) after switching from protease inhibitor or NNRTI to Nevirapine (Viramune®) and collecting of routinely observed laboratory data on lipids, and liver enzymes.

Inclusion Criteria:

• Patients suffer from HIV type 1 infection
• Patient is treated with antiretroviral protease-inhibitors or non-nucleoside reverse transcriptase inhibitors
• Patient has shown a depression of viral load before limit of detection (< 50 HIV-RNA copies/ml) for more than 6 months prior to visit 1
• Patient is male or female with age greater than or equal to 18 years
• Women have to be willing to use an effective barrier method of contraception for the duration of the observational study participation

Exclusion Criteria:

• Patient has clinically relevant laboratory findings (e.g., aspartate aminotransferase (AST) or alanine aminotransferase (ALT) > five times upper limit of normal (ULN))
• Patients is hypersensitive to Viramune® or to any of its excipients
• Patient is not able to abstain from treatment with ketoconazole, oral contraceptives, or other drug affecting CYP3A-metabolism
• Patients is breast-feeding
• Patient is pregnant
• Patient is a woman and does not use effective contraception

HIV treatment centres and HIV out-patient facilities