Water-cooled micro/minichannel heat sinks are an important component in managing the temperature of electronic components, particularly where high density of heat rejection is required. This study examines the potential to decrease the thermal resistance and enhance convective heat transfer of a serpentine heat exchanger by introducing chevron fins which create secondary flow paths. This novel design is found to significantly reduce both the pressure drop across the heat exchanger and the total thermal resistance by up to 60% and 10%, respectively, and enhance the average Nusselt number by 15%. A three-dimensional conjugate heat transfer model is developed and validated against experimental measurements, before being used to carry out a parametric study involving the chevron oblique angle, secondary channel width and heat flux. The design of the serpentine minichannel with chevron fins is then optimised in terms of the minichannel width, minichannel number and chevron oblique angle. A 50 point Optimal Latin Hypercubes Design of Experiment is constructed within the design variable space, using a permutation genetic algorithm, and accurate metamodels built using Radial Basis Functions. A Pareto front is constructed which enables designers to explore appropriate compromises between designs with low pressure drop and those with low thermal resistance. (C) 2017 Elsevier Ltd. All rights reserved.