We evaluated adherence to HIV treatments every 4 months during one year in 63 HIV-infected subjects using combination therapies including a protease inhibitor. A total of 18 subjects reported a high level of adherence, 14 in two evaluations, and eight a low level of adherence in all the three evaluations. The remaining 23 subjects (36.5%) reported different levels of adherence to treatment in the three evaluations. These findings suggest that the level of adherence to treatment changes markedly for each patient over time.