This study analyzes and optimizes a design for a convective straight trapezoidal fin using two-dimensional analytical method. Temperature distribution along the fin height in addition to fin lkength is presented to show the two-dimensional effect. The heat transfer, fin lenght, and fin height are optimized as a function of the ratio of convection characteristic numbers, fin shape factor, fin volume, and the overall wall resistance. Corresponding to the optimum conditions for several fin volumes, the fin effectiveness is shown as a function of convection characteristic number over the fin surface and fin shape factor.