We have evaluated CD4+-guided HAART interruption in 46 HIV+ patients with CD4+ > 500/microl and viral load undetectable since at least 3 years. This strategy resulted effective in a long mean period of treatment interruption (18 months) and safe. In fact, during the follow-up period there were no deaths, nor opportunistic infections. Reintroduction of HAART was due to: CD4+ fall under 200/microl (6 cases), acute retroviral syndrome (4), individual choice (2), asymptomatic thrombocytopenia (1), peripheral neuropathy (1), pregnancy (1). A low CD4+ nadir level was correlated with a short period of treatment interruption.