The interaction of a polychloroprene-based rubber lining used in corrosion protection with organic and aqueous media was investigated, For the organic solvents the solubility parameter proved to be a useful tool to explain qualitatively the strong variability in the change in weight due to swelling, In aqueous solutions of well dissolved electrolytes, water sorption is always lower than in distilled water, In ammonia and hydrochloric acid of high concentration however, the changes in weight are more pronounced, Thermoanalytical measurements show that in dependence of the water concentration within the solid, different states of sorbed water could be distinguished.