In this study the enhancement of heat transfer from a horizontal rectangular fin subjected to natural convection provided with rectangular perforations (1 by 5) is investigated. The perforated fin is compared with its equivalent solid one. The parameters considered are geometrical dimensions and thermal properties of the fin and that of the perforations. The study considered the gain in fin area and of heat transfer coefficients due to perforations. Also, it pointed out that for certain range of rectangular dimension and spaces between perforations there is an augmentation in heat dissipation over that of the equivalent solid one. Moreover, the heat transfer enhancement of the perforated fin increases as the fin thickness and thermal conductivity are increased.