Highly active antiretroviral therapies (HAART) represent a major advance in the treatment of HIV infection. Although with HAART a substantial suppression of viral replication can be obtained, eradication of the virus from the body cannot be achieved. Therefore, HIV-infected subjects have to be treated for the rest of their lives. Long term treatment will increase the frequency of: i) drug-related side effects; ii) onset of drug-resistant viral strains; iii) non-adherence of the patients to the treatment. Structured treatment interruptions (STI)-HAART might represent a feasible alternative and preliminary studies have shown that STI-HAART might induce immune control in patients treated in the early stage of infection. This regimen does not produce similar effects in patients treated during the chronic phase of the infection. However, there are some clinical data suggesting a possible role of hydroxyurea (HU) in inducing control of HIV replication in patients with established infection. In this manuscript in vitro and in vivo data indicating that HU might play a major role in the setting of STI-HAART will be presented.