Limited information is available on the etiology of acute lower respiratory infection (ALRI) particularly pneumonia in the rural community of developing countries since most etiological studies are carried out in the hospital settings. This study examined the etiology of pneumonia among young children in a rural community of Bangladesh. A cohort of 252 newborns was followed till 24 months of age during 1993-1996. Community health workers (CHWs) identified cases of ALRI during household surveillance and recommended hospitalization. On admission, nasopharyngeal aspirates (NPA) and blood were collected for bacterial and viral identification, and chest x-rays were done. Multiple regression analysis identified factors associated with a viral etiology. Physicians diagnosed 67 pneumonia; 45% of NPA were positive for viral agents of pneumonia, and respiratory syncytial virus (RSV) was predominant (81%); 6 of 48 blood cultures were positive. X-ray was done for 58 cases; 52% had pneumonic consolidation. Of the RSV cases, 33% were found in children without pneumonic consolidation. Children living in a one-room house were 3 times more likely to develop viral pneumonia (odds ratio (OR) = 3.67, CI 1.05-12.83) than children living in a larger house. Counseling on avoiding crowding where a newborn is accommodated might reduce pneumonia incidence.