The measurement system for the oxygen permeable resistance in cultured endothelial cells has been developed. Permeable resistance has been defined as thickness/permeability, (atm·sec/cm). The values of oxygen permeable resistance were measured using a quasi-steady method. Porcine endothelial cells were cultured on a collagen membrane cup. The membranes were placed as a diffusion barrier between two chambers. Chamber 1 was ventilated using a standard gas mixture with low oxygen partial pressure and chamber 2 was filled with phosphate buffer saline [PBS(+)] having high oxygen partial pressure thereby creating on oxygen partial pressure difference across the membrane. After the steady state was reached, the ventilation in chamber 1 was discontinued, and the change of oxygen partial pressure in the chamber 1 was monitored by O2 electrode. The values of oxygen permeable resistance were obtained by deducting the value of oxygen permeable resistance in the collagen membrane. In this study, the oxygen permeable resistance was measured with the maximum predictable error of 9-10%.