In this paper, we present a method by which we can significantly reduce energy consumption in sensor networks. In the proposed method, finding an optimum Cluster Head (CH) is performed by Genetic Algorithm (GA) and clustering the network environment is done by k-means algorithm. The results of simulation show that at the end of some certain part of running the proposed algorithm, the number of alive nodes increases, comparing with the same previous methods and this can lead to an increase in sensor network lifetime.