The separation and recovery of volatile hydrocarbon vapors from gasoline tank farm off-gases can in Europe be considered to be a state-of-the-art technology (1). A new application in the treatment of gasoline vapors is the installation of a membrane module in vapor return lines from petrol dispensers to storage tanks at gasoline stations to enhance the vapor recovery efficiency of this system. For solvent vapor recovery, some membrane systems have been installed in the chemical and pharmaceutical industry (2). This paper deals with design features and operating experience.