Considering temperature dependent heat transfer coefficient, an optimum longitudinal fin array is investigated. The heat transfer coefficient is assumed to vary with a power-law-type formula. The heat transfer from tips of an array fins is taken into consideration. For convenience of design, two approaches in the optimization of array system are given. The system is optimized by maximizing the heat dissipation of the fin array at a fixed total fin volume. It shows that the aspect ratios of fins for an optimized array is larger than that of a single optimum fin. The results of this work are all presented in dimensionless form for the convenience of design analysis. In addition, results from this study are compared with the experimental data of previous works.