Multiple U-typed producton lines are increasingly accepted in modern marufacturing system for the flexbility to adjust to changes in demand. This paper considers multiple U line balancing with the objective of minimizing cycle time considering the moving time of workforce given the number of workstation. Like the traditional line balancing problem this problem is NP-hard. In this paper, we show how genetic algorithm can be used to solve multiple U line balancing problem. For this, an encoding and a decoding method suitable to the problem are presented. Proper genetic operators are also employed. Extensive computational experiments are carried out to show the performance of the performance of the purposed algorithm. The computational results show that the algorithm is promising in solution quality.