The present study investigated thermal performance of silicon-based multiple micro-jet impingement cooling 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 heat flux of 100 W/cm2 was applied at one side of the silicon substrate, while at the other side jet impingement system was designed. The jet plate was consisted of many jet holes whereas computational domain was simplified by utilizing symmetric boundary conditions along the flow as well as lateral directions. The effect of various design parameters, namely, jet diameter, jet pitch, standoff (distance from jet exit to impingement surface) etc., have been analyzed at jet Reynolds numbers 100, 200 and 300 under laminar flow conditions. In view of the low pumping powers available through micro-pumping systems, low flow rates were applied for the analysis. The cross-flow effects of the spent-flow were investigated for finding out optimum design parameters and flow conditions for the heat sink. The temperature distribution was discussed for various values of jet diameter, standoff and jet-to-jet spacing. While a moderate thermal resistance of the heat sink was obtained under laminar flow conditions, high performance can be achieved for higher flow-rate turbulent flow conditions at the expense of excessive pressure-drop which would be investigated in future studies.