In spite of the fact that the principles of impinging stream reactors have been developed for more than half a century, the performance analysis of such devices, from the viewpoint of the mathematical modeling, has not been investigated extensively. In this study two mathematical models were proposed to describe particulate matter drying in tangential impinging stream dryers. The models were developed based on Markov-Chain analysis and the theory stirred tanks in series. The required parameters for each model were determined by using RTD data obtained in a tangential impinging stream dryer and then the governing equations were solved numerically. Comparing the models with available experimental data shows that the stirred tanks in series model successfully explains the drying behavior in impinging stream dryers. Nevertheless, the developed results of the model that is based on Markov-Chain analysis, are not in exact agreement with corresponding experimental data. Also, the effects of some operating parameters on performance of such dryers were investigated. The results indicate that the moisture removal efficiency of dryer increases when the solid to gas ratio and initial moisture content of particles decreases and the temperature of carrier gas increases.