The main goal of this evaluation was to measure the cost-effectiveness of a decentralised approach (primary health care clinics) versus a centralised approach (secondary health care facilities) in the Shiselweni region of Swaziland from a service provider perspective. The study showed that compared to the secondary health care facility ARV care in the primary health care clinics is both more effective and more expensive. Compared to the secondary health care facility, the extra cost the service provider has to pay for an ARV patient in the primary health care clinics to save an extra year of life is $652. In the study, a higher proportion of patients were retained in care in the primary health care clinics compared to the secondary health care facility. However, there was no difference in the proportion of patients who died within 12 months of initiation at these two levels. According to WHO standards, the decentralised ARV programme run in primary health care clinics in Nhlangano health zone is more cost-effective from a service provider perspective than the one run at the ARV centre in the secondary health care facility.