Lopinavir/ritonavir monotherapy is currently a well known and widely used strategy, while Lopinavir/ritonavir 800/200 mg once a day in a triple-therapy was approved a few years ago. The purpose of this study is to evaluate efficacy and safety of Lopinavir/ritonavir 800/200 mg monotherapy once a day.

Inclusion Criteria:

• Patients older than 18, HIV positive
• Patients receiving a monotherapy regimen (Lopinavir/ritonavir twice daily)during the last 6 months
• Undetectable viral load (<40 copies/ml) during the last 6 months
• Patients that accept participation in the study and sign the Informed Consent Form
• Childbearing females with negative pregnancy tests and using appropriate contraceptive measures

Exclusion Criteria:

• Opportunistic disease, cancer or any other active disease with specific treatment
• Active addiction to illegal drugs or active use of psychotropic drugs
• Mental retardation diagnosis, or mental dementia or severe psychiatric disorder (excluding major depression disorder solved > 3 months)
• Females who are breastfeeding or pregnant