A 16-channel pulse counter is presented, which has been designed primarily for the rationalization of tracer investigations with a great number of control points. It distinguishes itself by lossless recording of any parallel pulse trains, by the possibility to connect detectors (e.g. counters, scintillation counters) over distances up to 250 m, by low weight and small size, by equal measuring intervals in all channels, by automatic background correction and by high operational comfort. A computer programme has been elaborated and is available especially for the evaluation of test series arising with the measurement of gas exchange (air exchange).