A mathematical model is described that accounts propagating waves of free cytoplasmic Ca arising from the activation of single Ca release channels. The [Ca] wave moves along the surface of intracellular stores and is supported by the subsequent activation of neighbouring Ca release channels. The model considers both activation and inactivation of the channels and the buffering of excess Ca in the cytoplasm. This non-dissipating wave of Ca concentration is shown to exist only for a certain range of the single channel conductance and the rate of Ca buffering in a cytoplasm. The wave velocity depends also on the other model parameters and generally comprises the values 1-300 microns sec-1. Data obtained are used to discuss the possibility of the delivery of free Ca concentration pulse from the surface membrane to a given point of the cell interior.