In an industrial production line, efficiency is considered to be a crucial factor. Efficient production line results in increased production and efficient utilization of all available resources. This research describes a type of robotic assembly line balancing problem, in which the assembly tasks are to be allocated to workstations, and each workstation needs to be allotted with a robot which performs these tasks in minimum time with an objective of maximizing line efficiency, Smoothness Index and cycle time are calculated for the efficient assembly line. In this paper, a differential evolution approach is proposed to solve straight and U- shaped robotic assembly line. Performance of the algorithm is tested on the benchmark datasets for both the problems and the results are reported. © Springer International Publishing Switzerland 2015.