Diffusion coefficients of five elastomer membranes, viz., nitrile butadiene rubber, styrene–butadiene rubber, ethylene–propylene–diene terpolymer, neoprene, and natural rubber with acetic acid and dichloroacetic acids have been obtained from gravimetric sorption experiments. For acetic acid, the diffusion seems to follow the expected Fickian mechanism whereas for dichloroacetic acid, the diffusion appears to follow the non-Fickian mechanism for natural rubber and nitrile butadiene rubber membranes. While most membranes remain intact during immersion experiments, only natural rubber has shown degradative reactions. The concentration dependence of diffusivity has also been studied.