The permeability coefficients of saturated and non-saturated vapors of benzene, hexane and cyclohexane through flat polymer membranes (low density polyethylene BRALEN FB2-30 and polyether-block-amide PEBA4033-PE) by two different experimental techniques at 298.15 K are reported. The permeation data have been obtained using the differential flow permeameter and sorption ones by glass sorption apparatus with McBain's spiral balance. The so-called stationary (steady) diffusion theory has been applied for evaluating the permeability coefficients from sorption (equilibrium) data and obtained values have been compared with the permeability coefficients from permeation (steady-state) measurements. In the case of relative lower vapors sorption in polymers (hexane and cyclohexane) good agreement between permeability coefficients from sorption and permeation is obtained. Hence, this paper proves the possibility to estimate the permeability coefficients of organic vapors from sorption data without need of performing the permeation experiments. (C) 2004 Elsevier B.V. All rights reserved.