In this study, a sinusoidally oscillating jet injected through a rectangular slot between two infinite horizontal plates was considered. Bottom plate was kept at constant temperature and the top plate was insulated. The oscillating air jet, issued from a rectangular slot on the top plate was impinged on the bottom hot plate. A computer program was developed by using the control volume technique and SIMPLE algorithm. Using this computer program, flow and heat transfer characteristics of the jet flow were numerically analyzed. The effects of the H/W, oscillation amplitude and oscillation frequency on the flow and heat transfer were investigated. It was observed that the stagnation point Nusselt number decreases with the increasing H/W ratio, but variation in the Nusselt number for H/W greater than 2 is very small. It is also observed that the oscillation of jet has no effect on stagnation Nusselt number when H/W is approximately less than 1.5. However, at the cases when H/W is greater than 1.5 the oscillating increases the Nusselt number with respect to the Nusselt number of a steady jet.