The experimental data on oxygen flux from arterioles in the hamster cheek pouch retractor muscle [L. Kuo and R. N. Pittman, Am. J. Physiol. 254 (Heart Circ. Physiol. 23): H331-H339, 1988] were analyzed under the assumption that the permeability to oxygen is the same in both perfused and unperfused tissue; permeability is defined as the product of the diffusion and solubility coefficients. However, our analysis indicated that the observed oxygen flux was inconsistent with this assumption and that permeability to oxygen of a blood-perfused tissue may be an order of magnitude higher than previously assumed.