One of key technologies of 5th generation mobile networks is introducing small cells, such as femtocells and picocells, to supplement existing macrocells, and this results in high heterogeneity in mobile networks. Cell association, which selects a base station for each user to connect to, is a fundamental issue to optimize the performance and utilization of heterogeneous networks. This paper develops a heuristic cell association algorithm for heterogeneous networks, which adopts the minimum throughput among users as a criterion to determine user to cell associations. Through simulation experiments, we show that the proposed algorithm increases traffic accommodated in the network as well as it achieves high total and minimum throughput.