This study presents the thermal performance of laterally perforated plate-fin heat sinks (LAP-PFHSs) with different numbers (N-p) and diameters (D-p) of circular perforations. Based on the same plate fin dimension, the available diameter of circular perforations is limited by their number. The largest diameters of perforation for N-p = 14, 27 and 75 are 10 mm, 7 mm and 4 mm, respectively. The computational results of solid fin heat sinks (SFHSs) and LAP-PFHSs are validated with the measured data and experimental data from the available literature. The comparison results of LAP-PFHSs give the mean absolute error of about 3.6% and 5.3% for the pressure drop and thermal resistance, respectively. According to the numerical results, the LAP-PFHS with D-p = 3 mm and N-p = 75 exhibits the highest heat transfer rate, about 11.6% higher than that of the SFHS. Finally, the thermal performance factor, which is a consideration of the Nusselt number and friction factor, is proposed to find the suitable design parameters. Under the same conditions, the optimized LAP-PFHS demonstrates 10.6% greater thermal performance and 28% lower volume of heat sink material than SFHS. (C) 2019 Published by Elsevier Ltd.