A study was undertaken to develop and apply the first-order Markov model in generating the synthetic stream flow for Adada, Ivo, Otamiri, Imo and Ajali rivers located in South East Nigeria. The best-fit probability distributions for the maximum annual stream flows were lognormal, Weibull, normal and lognormal for Adada, Ajali, Ivo, Otamiri and Imo (Umuokpara) rivers respectively were used in simulating the associated random deviates. The stream flow data for 10 years (1980 to 1989) were used to develop the model and to predict the stream flow. The model performance was evaluated with the aid of the coefficient of determination (R2). The results indicated a satisfactory performance as evidenced by R2 values of 51.69%, 31.3%, 21.4%, 33% and 21% for Adada, Ajali, Ivo, Otamiri and Imo rivers respectively. The developed models were used to generate 50-year synthetic stream flows of these rivers. The study showed that the annual Markov models have proved to be a powerful tool to extend 10-year record of maximum annual runoffs.