The goal of this study was to develop an evaluation method of antiretroviral treatment adherence from a hospital pharmacy and to identify one or more factors that influenced this adherence, such as patient or treatment characteristics. The HIV patients included in this study were based, for the major part, in Saint-André hospital and collected their medication from this hospital pharmacy. They were all delivered a renewable prescription that should have comprised two successive delivery stamps. A total of 186 patients was included. For the adherence analysis, the delay between two successive deliveries was measured. We have specified three different categories of patients: adherent, non-adherent and intermediate, according to a definition of adherence accepted by many authors. We have demonstrated that the only antiretroviral therapeutic class associated with poor adherence was the protease inhibitors, in particular nelfinavir, which requires food to be taken at the time of administration. This can pose difficulties for those patients who lunch at their workplace and consequently affect adherence. This study allowed us to demonstrate that a less subjective adherence evaluation can be easily carried out from a hospital pharmacy.