The presence of respiratory syncytial virus (RSV) and several cytokines and cell adhesion molecules in middle ear effusions and mucosal tissues was evaluated using polymerase chain reaction. RSV genomic sequences were detected in 23 (52.7%) of 44 middle ear effusions tested. The sequences were detectable at an even higher rate (82.4%) in effusions of children in whom infectious virus was detected in the nasopharynx. All samples with the RSV genome contained the mRNA for interleukin-1 beta and -6 and tumor necrosis factor-alpha. The messages for these cytokines, together with intercellular adhesion molecule-1, endothelial leukocyte adhesion molecule-1, and vascular cell adhesion molecule-1, were detected in human middle ear mucosal organ cultures infected in vitro with RSV. Our results suggest that the enhanced synthesis of proinflammatory cytokines and cell adhesion molecules in the middle ear infected with RSV may contribute to the inflammatory processes in otitis media.