The transport of methylene chloride into PEEK resin systems following six successive sorption/desorption cycles was investigated. The sorption and desorption processes in neat PEEK with different morphologies and with varying degrees of crystallinity (from 1 to 29%) were compared to chopped-carbon-fiber and carbon-fiber-laminate composites. The amount of methylene chloride sorbed during an 80-min immersion varied from less than 1 wt % in the composites to 37 wt % in the amorphous neat PEEK. During each cycle the solvent was desorbed at 95°C for 338 h. With the exception of the laminate, the sorption/desorption process is essentially independent of cycling. Furthermore, when the desorption processes are viewed in normalized form, i.e., fractional weight loss as a function of time, the desorption appears identical in all samples investigated. Although the maximum amount of solvent retained by the laminate was small, less than 0.1 wt % after the first cycle, it did increase to almost 0.15 wt % after 5 cycles.