Optimal antiretroviral strategies for HIV-infected patients still need to be established. To this end a decision tree including different antiretroviral strategies that could be adopted for HIV-infected patients was built. A 10-year follow-up was simulated by using transitional probabilities estimated from a large cohort using a time-homogeneous Markov model. The desired outcome was for patients to maintain a CD4 cell count of >500 cells/mm3 without experiencing AIDS or death. For patients with a baseline HIV viral load ≥5 log10 copies/ml, boosted protease inhibitor-based immediate highly active antiretroviral therapy (HAART) allowed them to spend 12% more time with CD4 ≥500/mm3 than did delayed HAART (6·40 vs. 5·69 and 5·57 vs. 4·90 years for baseline CD4 ≥500 and 350-499/mm3, respectively). In patients with a baseline HIV viral load ≤3·5 log10 copies/ml, delayed HAART performed better than immediate HAART (6·43 vs. 6·26 and 5·95 vs. 5·18 for baseline CD4 ≥500 and 350-499/mm3, respectively). Immediate HAART is beneficial in patients with a baseline HIV viral load 5 log10 copies/ml, whereas deferred HAART appears to be the best option for patients with CD4 ≥350/mm3 and baseline HIV viral load <3·5 log10 copies/ml.