The HZGA San Roque Hospital (an Acute Hospital at La Plata, Argentina) assists 40 HIV patients. The present study was carried out due to the lack of adherence to the High Activity Anti-Retroviral Therapy (HAART) because of the late withdrawal of medication. The present work was implemented on HIV patients who withdraw medication from the Pharmacy Department at the Hospital. Research period lasted 12 months. The aims of this work were to quantify the degree of adherence to the treatment, to assist patients by means of pharmaceutical care so that they reach a 90 % of adherence to the treatment, to analyse the relationship between the understanding of the treatment and its administration and the degree of adherence, and, finally, to analyse the relationship between viral load (VL) and adherence. The study showed that containment and information help to raise the level of patients' adherence to HAART in 29 %. The patients' responsibility and commitment to the treatment also increased, as well as CD4 values; VL, on the other hand, decreased with respect to the beginning of the study. The interrupt far TIMID (less than 0.10) shows an improvement of 15.8 % in the number of patients who interrupted their treatment is also reflected in the survey of adherence where we have an increase of 26.2 %.