The primary objective of this study was to examine the effects of enzyme treatment on chemical compositions and production of reducing sugars in palm (Elaeis guineenis) kernel expeller (PKE). PKE was incubated in 80% water content at 55°C for 18 h with enzyme or without enzyme (as control). Crude protein (CP) and gross energy (GE) contents of PKE were not significantly different (P>0.05) between the control and enzyme treated PKE; averaged 17.95% for CP and 15.88 MJ/kg for GE. However, ether extract (EE) neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose and cellulose contents of enzyme treated PKE decreased (P<0.01) by approximately 34.6, 26, 20, 35.7 and 22.1%, respectively, compared with the control. Total content of reducing sugars (mannose, glucose and galactose) of the enzyme treated PKE increased by approximately 200 folds compared to the control (P<0.01). Enzyme treated PKE had higher (P<0.01) cellulase and mannanase activities but not αgalactosidase. Key word: Enzyme treated palm kernel expeller, chemical composition, reducing sugars, palm kernel expeller.