Warpage is one of the common defects seen in thin-walled injection moldings. There are several ways to reduce warpage in injection molding process such as optimizing process conditions, changing mold design or part design. In this study, warpage of the injection molded thin-walled chassis part of an air conditioner was investigated by finite element method (FEM) and response surface method (RSM). The material was polypropylene with 20% glass fiber and 4% chemical foaming agent. The key parameters in FEM analysis and RSM were cooling time, mold temperature and flow rate of the coolant. It has been seen that mold temperature was the most significant parameter on warpage. RSM and FEM were satisfactorily successful in predicting the warpage values.