Antiretroviral treatment roll-out programmes in Africa often have difficulties to cope with the increasing number of clients. Based on the findings of a survey carried out in 2005 that showed long waiting times, innovative organizational changes (nurse visits and pharmacy-only refill visits) were introduced in our clinic. In August 2007, the survey was repeated to evaluate the impact of these changes. During both surveys we used the same standardized questionnaire. In 2007, 400 patients visited the clinic on the study day compared to 250 in 2005. The median time spent at the clinic decreased from 157 minutes in 2005 (range 22-426) to 124 minutes (15-314). All the waiting times for different services decreased except the time between the visit to the triage nurse and the doctors' visit. A similar methodology could be used by other health services to evaluate and compare different models of care.