We tested the hypothesis that human immunodeficiency virus (HIV)–infected adults have a specific defect in anti-pneumococcal capsular polysaccharide (Pn-specific) immunoglobulin (Ig) in fluid obtained from the lower respiratory tract. Higher levels of total IgG and IgM were present in bronchoalveolar lavage samples from HIV-infected subjects than in those from HIV-uninfected subjects. Pn-specific IgG and IgM in bronchoalveolar lavage samples were not significantly different between HIV-infected and -uninfected subjects. After pneumococcal infection, HIV-infected patients had higher bronchoalveolar lavage levels of Pn-specific IgG than HIV-infected patients without recent infection (geometric means, 387 vs. 30 ng/mL, P=.001)