In this study, the experimental and numerical investigation of forced convective heat transfer in an optimized rectangular micro-channel heat sink (MCHS) is analyzed using water as the working fluid. The optimization of MCHS has carried out by using CVM (Constant Volume Method) and VVM (Variable Volume Method). From the optimization, it is clear that aspect ratio three which gives the better heat transfer coefficient and lower pressure drop values as comparing with adjacent aspect ratios. A numerical investigation of MCHS based on the finite volume method. The numerical results are validated by comparing the predictions with analytical solutions and experimental data. High heat flux and high coefficient of heat transfer obtained by reducing the core volume of the channel and changing operating conditions. The Optimized micro-channels geometry has a width of 700 μm and a depth of 2100 μm, and is separated by a 350 μm wall. The microchannels are made on cooper plate by using a wire Electro Discharge Machining. The pressure drop and heat transfer investigation is carried out for various Reynolds Number. The obtained results are also compared with the correlation available in literature and presented in the paper.