The present study investigates thermal performance of a silicon-based multiple micro-jet impingement heat sink for thermal management of electronics. Three-dimensional numerical analysis was performed for steady incompressible laminar flow and conjugate heat transfer through a finite volume solver. A moderate heat flux, 100 W/cm2, is applied at the one end of the silicon substrate, while at the other end jet impingement system is designed. The jet plate is consisted of many jet holes whereas computational domain was simplified by utilizing symmetric boundary conditions across a lateral pitch as well as a central plane in x-direction. The effect of design parameters, namely, jet diameter and jet pitch has been analyzed at constant jet Reynolds numbers under laminar flow conditions on the performance of the heat sink. In view of the low pumping powers available from the micro-pumping devices, low flow rates are applied for the analysis. The crossflow effects of the spent-flow are investigated for finding out optimum design parameters of the heat sink. The temperature distribution is discussed for number of jets, jet diameter and jetto- jet spacing across the flow direction. While a moderate thermal resistance of the heat sink was obtained under laminar flow conditions, high performance can be achieved for turbulent flow conditions at the expense of excessive pressure drop which would be investigated in future studies.