Objective: The present article estimates the cost and outcomes of second-line antiretroviral therapy. The cost of second-line drugs is generally higher than that of first-line drugs and it is expected that the absolute number of patients on second-line antiretroviral therapy will increase over time. This information is crucial for planning and budgeting. Methods: Resource utilization and outcome data were extracted for patients who initiated standard second-line therapy. Resource usage was measured from second-line initiation for 12 months and outcomes were determined at 12 months. Unit costs were applied to resource usage using standard costing techniques. Costs were classified into drug, laboratory, visit, and fixed costs. Outcomes at 12 months were determined using attendance status, diagnostic results, and treatment status. Average cost per patient and average cost per outcome were reported. Results: Of the 293 participants in the study cohort, 58% remained in care and responding, 15% were in care but not responding, and 26% were no longer in care. During the 12 months following second-line initiation, the average cost per participant was $1037. Most of the cost per patient was attributable to drugs (71%), 13% to laboratory tests, 10% to clinic and pharmacy visits, and 6% to infrastructure and other fixed costs. Second-line therapy was 2.4 times more expensive per year in care than first-line therapy. Conclusion: The gradual increase in second-line numbers that can be expected as treatment programs mature may cause a meaningful increase in the overall average cost per patient treated.