Abstract: In this paper, a stochastic approach, namely, a Markov chain with transient and absorbing states, has been used to generate the residence time distribution for any conceivable flow model. All calculations have been carried out with the aid of a computer. The present results compare favorably with those obtained by earlier investigators. However, the present approach is applicable to complex flow systems for which the deterministic mathematical description of them is very complicated, or impossible. The mean and variance of the residence time distribution are readily obtained from this model. Potential applications of this model are numerous, especially for particulate systems.