The heat sinks, with the total heat transfer area of 20 x 20 mm(2) and an array of 625 staggered micro square pin fins of 559 x 559 mu m(2) or 445 x 445 mu m(2) cross section by 3 mm height were fabricated on a copper test section. Using deionized water as coolant liquid, the flow and heat transfer performance of the high pin fins were studied with the Reynolds number ranging from 60 to 800. For the 445 x 445 mu m(2) cross section pin fin heat sink, the heat dissipation could reach 2.83 x 10(6) W/m(2) at the flow rate of 57.225 L/h and the surface temperature of 73.4 degrees C. The experimental data also showed that the pressure drop and the average Nusselt number increased with the fin Reynolds number. The heat resistance decreased with, with its decreasing rate inversely proportional to, the pressure drop. Since four chosen previous correlations overestimate the flow and heat transfer performance of the present sinks, we also proposed two new correlations for the average Nusselt number and pressure drop prediction. (C) 2011 Elsevier Ltd. All rights reserved.