Effect of jet-plate spacing to jet diameter ratios on the jet impingement heat transfer and pressure drop of TiO(2 )nanofluids have been presented. The heat sink is fabricated from the aluminum by the wire electrical discharge machine with the length, the width and the base thickness of 50, 50, 3 mm, respectively. The parameters and the ranges under consideration are in the jet-plate spacing to jet diameter ratios (H/D = 0.8-4.0), the nanofluids concentrations (0.005-0.015% by volume), and mass flow rates (8-12 g/s). It can be found that the jet-plate spacing to nozzle diameter ratios have significant effect on the temperature and flow behaviors of jet impingement which results in increase turbulent intensity and then higher heat transfer rate. There is reasonable agreement between the predicted results and the measured data and gives average error of 3.34%. (C) 2017 Elsevier Ltd. All rights reserved.