Technical Abstract: Wheat bran was extruded in a twin-screw extruder at five specific mechanical energy (SME) levels (0.120, 0.177, 0.234, 0.291 and 0.358 kWh/kg dry basis), and their cholesterol-lowering effects were compared with those of unprocessed wheat bran when fed to four-week-old male golden Syrian hamsters (n=10 per treatment) for three weeks. Diets contained 10% total dietary fiber, 10.3% fat, 3% nitrogen and 0.4% cholesterol. Plasma total very low density lipoprotein cholesterol was significantly lower with 0.120 kWh/kg extruded wheat bran diet compared with the unextruded wheat bran control. Total triglycerides were significantly lower with 0.120 and 0.177 kWh/kg wheat bran diets compared with those fed 0.291 and 0.358 kWh/kg extruded wheat bran diets. Cholesterol digestibility, total liver cholesterol and total liver lipids were significantly lower with all the extruded wheat bran diets compared with the unextruded wheat bran control. Cholesterol digestibility for the 0.291 kWh/kg wheat bran diet was also significantly lower than all other extruded diets. Significantly more sterol were excreted with diets containing 0.291 and 0.358 kWh/kg extruded wheat bran compared with the unextruded wheat bran control. Wheat bran extruded with 0.291 kWh/kg diet resulted in a 13% reduction in plasma cholesterol, a 29% reduction in low density lipoprotein cholesterol and a slight (1%) increase in high density lipoprotein cholesterol. Considering lowest cholesterol digestibility, significantly higher sterol excretion, desirable plasma lipoprotein cholesterol profile, significantly lower liver weight, total liver lipids and liver cholesterol, wheat bran extruded at 0.291 kWh/kg appears to have the most desirable healthful potential. Data suggest that the cholesterol-lowering potential of wheat bran could be enhanced by optimizing the energy input used in the extrusion process.