Master production scheduling is an e ective phase of production planning, which ends in production scheduling and magnitude of di erent products in a company. This problem requires investigating a wide range of parameters, regarding demand, manufacturing resource usage, and costs. Uncertainty is an intrinsic characteristic of these parameters. In this paper, a model is developed for master production scheduling under uncertainty, in which demands, as time-dependent variables, are considered as stochastic variables, while cost and utilization parameters, with cognitive ambiguity, are expressed as fuzzy numbers. A hybrid approach is also proposed to solve the extended model. The application of the proposed method is examined in a practical problem of a polyethylene pipe and tting Co. in Iran. The result showed a high degree of applicability.