Since the avian antigen is one of the important causative antigens in hypersensitivity pneumonitis, measurement of bird-specific antibody should be readily available. We measured IgG and IgA antibodies against pigeons and budgerigars by the ImmunoCap system in bird-related hypersensitivity pneumonitis (BRHP) to evaluate their diagnostic utility. In acute BRHP, antibodies markedly increased and showed high sensitivity and specificity ranging from 75-100% based on the cut-off values determined by ROC analysis. In chronic BRHP, antibody reactivity slightly increased, showing a sensitivity of 27-73% and specificity of 45-100%. Pigeon antibodies evaluated by the ImmunoCap system showed a good correlation with anti-pigeon dropping extract antibodies measured by ELISA. In conclusion, measurement of antibodies against pigeons and budgerigars are helpful for the diagnosis of BRHP.