Summary Objective To study the effect of age on several outcomes among 187 antiretroviral-naive infected patients who started highly active antiretroviral therapy (HAART) with ≤200 CD4 +/μl. Methods We carried out a retrospective study to determine the hazard ratio (HR) to reach an outcome in patients who experienced a change from the baseline in CD4 + counts of at least +100, +200, +300, +400 and +500 cells/μl at any moment during the follow-up and the odds ratio (OR) of achieving and maintaining a CD4 + value above a certain setpoint during at least 6, 12 or 18 months. Results The adjusted HR for an increase of +400 CD4 +/μl and +500 CD4 +/μl were 1.3 (95% CI: 1.1; 1.5) and 1.3 (95% CI: 1.1; 1.6) times slower for each additional 5 years of age at baseline. In addition, for every 5 years of extra age, the adjusted OR to achieve an absolute CD4 + cell count >500/μl at 6, 12 and 18 months after the initiation of HAART were 2.2 (95% CI: 1.5; 3.2), 1.8 (95% CI: 1.2; 2.6), and 1.8 (95% CI: 1.2; 2.9) times less likely, respectively. We also found that patients ≥45 years old had worse complete CD4 + recovery (CD4 + > 500 cells/μl) than patients <45 years old. Conclusion The CD4 + recovery after HAART is a prolonged and continuous process which extends for several years. Age at baseline is inversely correlated with the magnitude and speed of CD4 + recovery among HIV-1 infected patients.