A disassembly process is usually characterized by a high level of uncertainty due to the quality of End-of-Life products. This paper presents an efficient approach for designing disassembly lines with the objective to maximize the line profit. Task times are assumed to be random variables with known probability distributions. An AND/OR graph is used to model the precedence relationships among tasks and subassemblies and the disassembly alternatives. A Monte Carlo sampling based exact solution method is developed to deal with uncertainties. Results of experiments on problem instances are presented.