Surfactant protein D (SP‐D) is an important component of the pulmonary host defense system. We hypothesized that bronchoalveolar lavage (BAL) SP‐D levels are lower in children presenting with recurrent bronchitis, providing evidence for a role of SP‐D in human respiratory diseases. SP‐D levels in BAL were measured in 45 children, who suffered from recurrent bronchitis for an average of 2–3 yr. Clinical outcome was assessed 2 yr after BAL. For comparison, BAL fluids from 15 control children without respiratory symptoms were evaluated. Among the 45 children with recurrent bronchitis, 12 had no SP‐D in their BAL at the time of investigation. These SP‐D‐deficient patients had more frequently pneumonias and their long‐term outcome was worse than that of the children with detectable SP‐D. No genetic cause could be identified for the SP‐D deficiency. Among the children with recurrent bronchitis and SP‐D clearly detectable in BAL, those with the diagnosis of allergic asthma had threefold elevated levels compared with controls. In accordance with animal and in vitro data, elevated SP‐D concentrations in BAL may represent an up‐regulation due to allergic airway inflammation. In contrast, SP‐D deficiency due to consumption or failure to up‐regulate SP‐D may be linked to pulmonary morbidity in children.