In this study, change of hardness value of polyurethane foam used in furniture upholster was investigated. The dimension of test samples was determined that based on the surface of one seat 45x45x10 cm. The change of hardness value of test samples was determined after testing of fatigue performance applied to7000 times at 50, 70, 90 and 120 kg. Density value of test samples was determined. Result shown that the high density foam was affected less then low density foam during the fatique performance.