The effects of the Rhynchosia nulubilis extracts on serum lipid concentrations were evaluated in rats. Forty-two male Sprague-Dawley rats weighing 100±10g were divided into six groups and fed high fat and high cholesterol diets for four weeks. Experimental groups were administered with following diets; basal fat diet(control) and basal and high fat diets with 1% cholesterol and Rhynchosia nulubilis extract(40mg/kg, 400mg/kg and 4000mg/kg). The concentrations of serum triglyceride in rats fed the Rhynchosis mulubilis extract, high fat, 1% cholesterol, and RN-HFC(-40, -400, -4000mg/kg) groups were lower than those in other groups. The concentrations of total cholesterol in the RN-HFC (-40, -400, -4000mg/kg) groups were lower than those in fat diet groups. The concentrations of HDL-cholesterol in serum of the RN-HFC(-40, -400, 4000mg/kg) groups were significantly higer than those of other groups. The levels of LDL-cholesterol in serum of the RN-HFC(-40, -400, -4000mg/kg) groups were tended to be lower than those of other groups. These results suggest that Rhynchosia nulubilis extract may reduce elevated levels of serum lipid concentrations in rats fed high fat diets.