Polymer synthetic jets driven by cantilever PZT bimorphs were fabricated and their cooling performance on a heat sink fin tip surface was investigated. Geometrical parameters of the synthetic jets, including cavity size, cavity depth, orifice size, orifice length, and diaphragm thickness, were optimized for increased jet velocity and high cooling performance using the Taguchi test method. Based on the test results, a synthetic jet with an optimized structure was fabricated. Measurements showed that the optimized jet can produce a peak air velocity of 50 m/s at 900 Hz from a round orifice 1.0 mm in diameter. The power consumption of the jet in this condition is 0.69 W and the total mass is 6 g. Using the optimized synthetic jet, a heat transfer coefficient of 576 W/m2K was achieved on the fin tip, indicating an increase of 630% over natural convection values.