An appropriate sequence of assembly operations increase the productivity and enhance product quality there by decrease the overall cost and manufacturing lead time. Achieving such assembly sequence is a complex combinatorial optimisation problem with huge search space and multiple assembly qualifying criteria. This paper presents a novel hybrid artificial intelligent technique, which executes Artificial Immune System (AIS) in combination with the simulated annealing (SA).The proposed AIS-SA algorithm aims at enhancing the performance of AIS by incorporating SA as a local search strategy to achieve global optimum solution for assemblies with large number of parts. The proposed algorithm is implemented on a mechanical assembly composed of 07 parts joined by several connectors. The method is found to be successful in achieving global optimum solution with less computational time compared to traditional artificial intelligent techniques. Computational results indicate that the proposed AIS-SA algorithm has superior performance in terms of solution quality and computational time. © 2017 Elsevier Ltd.