BACKGROUND: Increased incidence and prevalence of asthma have been documented for perinatally HIV-infected youth 10 to 21 years of age compared with HIV-exposed uninfected (HEU) youth. OBJECTIVE: We sought to perform objective pulmonary function tests (PFTs) in HIV-infected and HEU youth with and without diagnosed asthma. METHOD: Asthma was determined in 370 participants (218 HIV-infected and 152 HEU participants) by means of chart review and self-report at 13 sites. Interpretable PFTs (188 HIV-infected and 132 HEU participants) were classified as obstructive, restrictive, or normal, and reversibility was determined after bronchodilator inhalation. Values for HIV-1 RNA, CD4 and CD8 T cells, eosinophils, total IgE, allergen-specific IgE, and urinary cotinine were measured. Adjusted prevalence ratios (PRs) of asthma and PFT outcomes were determined for HIV-infected participants relative to HEU participants, controlling for age, race/ethnicity, and sex. RESULTS: Current asthma was identified in 75 (34%) of 218 HIV-infected participants and 38 (25%) of 152 HEU participants (adjusted PR, 1.33; P = .11). The prevalence of obstructive disease did not differ by HIV status. Reversibility was less likely in HIV-infected youth than in HEU youth (17/183 [9%] vs 21/126 [17%]; adjusted PR, 0.47; P = .020) overall and among just those with obstructive PFT results (adjusted PR, 0.46; P = .016). Among HIV-infected youth with current asthma, serum IgE levels were inversely correlated with CD8 T-cell counts and positively correlated with eosinophil counts and not associated with CD4 T-cell counts. HIV-infected youth had lower association of specific IgE levels to several inhalant and food allergens compared with HEU participants and significantly lower CD4/CD8 T-cell ratios (suggesting immune imbalance). CONCLUSION: Compared with HEU youth, HIV-infected youth demonstrated decreased reversibility of obstructive lung disease, which is atypical of asthma. This might indicate an early stage of chronic obstructive pulmonary disease. Follow-up into adulthood is warranted to further define their pulmonary outcomes.