Modeling of gas permeation in hollow-fiber or spiral wound modules necessitates considering the effect of permeate pressure variation along the module length which could have a significant effect on the prediction of the exit compositions and membrane area requirements depending on the membrane characteristics and module geometry. The transport equations governing the permeator performance are a set of coupled nonlinear differential equations. The complexity of the solution procedure for these equations increases with the number of components in the mixture and consideration of pressure variation. Thus, there is a need for simplified solution methodologies which could reduce the computational efforts. This paper presents a solution methodology to solve the multicomponent gas permeator transport equations in a countercurrent flow pattern, taking the permeate pressure variation into consideration. The present method yields analytical expressions for flow rates, permeate pressure, membrane area, and compositions along the length of the permeator.