The knowledge of the barrier properties of high polymers is necessary e. g. for the application in packaging. This requires reliable and fast permeability measurement techniques. During the last few years the traditional setup using mercury manometers as a gas detector has been replaced, e. g. by capacitance manometers with higher resolution and accuracy, by detectors used in gaschromatography (thermal conductivity detector and flame ionization detector), a detector specific for H2O and electrochemical detectors specific for O2. Sensitivity, response time and calibration procedure of different methods are compared. For practical applications the electrochemical detector specific for O2 seems to be the best compromise.