Abstract: A biofeedback training system is provided in which portable, self-contained modular units may be used independently for relatively simple biofeedback training purposes by a layman or may be connected to a central processor adapted to provide more sophisticated processing of the signals monitored by the portable unit under supervision of a specialist. The system thus provides a partitioning of functions in which physiological signals are monitored and preprocessed in the portable unit, and when the portable unit is connected to the central processor, these preprocessed signals are then fed into the central processor where elaborate filtering, thresholding, converting and integrating functions take place in a biofeedback system. The central processor is capable of receiving inputs simultaneously from multiple portable units.