Uteroglobin-related protein 1 (UGRP-1) is a protein specifically secreted in airways, where it could play an anti-inflammatory role. We developed a sandwich enzyme-linked immunosorbent assay (ELISA) allowing the detection of UGRP-1 in serum, urine, and amniotic and pulmonary fluids. Concentrations of UGRP-1 determined by ELISA and latex immunoassay were correlated in sputum and bronchoalveolar lavage fluid (BALF). The pattern of UGRP-1 concentration resembled that of Clara cell protein, both proteins occurring in high concentrations in amniotic fluid, sputum and BALF and in much lower concentrations in serum and urine. These findings suggest that UGRP-1 might serve as a biomarker of respiratory epithelium integrity.