In this paper heat transfer enhancement by multiple jets impingement of array of 9 (3×3), 16 (4×4), and 25 (5×5) jets were investigated. Local Nusselt number and Local effectiveness of jet impingement for arrays of 9, 16, and 25 were reported. The influence of jet interference and jet fountain on Nusselt number and effectiveness was investigated. Jet interference reduces the strength of jets and deteriorates heat transfer. Fountain of jet creates the recirculation of air which reduces the heat transfer. Heat transfer by multiple jet impingement of heated air is reported in this paper. Local Nusselt number and local effectiveness decrease with increases of a nozzle to plate spacing (H/d). Effectiveness at the stagnation point is 1 for H/d equal to 2 and 4 and decreases for higher H/d.