AIM: To investigate the expression of aquaporins-1 (AQP-1) in cultured bovine corneal endothelial cells and to explore the role of AQP-1 in corneal endothelial fluid transport. METHODS: The bovine corneal cells were cultured in DMEM containing 200mL/L neonate bovine serum. AQP-1 expression in the bovine corneal endothelial cells was detected with immunohistochemistry method before and after treatment of the cells with aquaporin inhibitor,p -chloromercuribenzene sulfonate. The osmotic water permeability was determined by monitoring volume changes of cultured bovine corneal endothelial cells. RESULTS: Positive staining was used to reveal the AQP-1 expression in the membrane of cultured bovine (in brown color). The reading of osmotic water permeability of the cultured bovine corneal endothelial cells before treatment with p -chloromercuribenzene sulfonate was 0.044±0.005cm/s, which significantly decreased to 0.017±003cm/s after treatment (n =15). CONCLUSION: AQP-1 expressed in the membrane of cultured bovine corneal endothelial cells may play an important role in fluid transport of corneal endothelial cells. Alteration of the AQP-1 expression may cause abnormal corneal function and corneal edema.