PURPOSE: To provide a grease compsn. which has excellent flaking preventive properties and heat resistance and is particularly suitable for use in plunging type constant velocity ball joint or fixation type constant velocity ball joint by comprising a base oil, a specified diurea compd., molybdenum disulfide, and a specified extreme pressure agent.

CONSTITUTION: This grease compsn. for a constant velocity joint comprises: (A) a base oil, such as a mineral oil or an ester synthetic oil; (B) a diurea compd. represented by the formula: R1NH-CO-NH-C6H4-p-CH2-C6H4-p-NH-CO- NHR2 (wherein R1 and R2 each represent 6-7C aryl or cyclohexyl); (C) molybdenum disulfide having an average particle diameter of 0.25 to 10 μm as measured with a Fisher sieve; and (D) a metal-free extreme pressure agent contg. 15 to 35 (wt) % sulfur and 0.5 to 3% phosphorus. Pref., the contents of the components B, C, and D are 5 to 25%, 1 to 5%, and 0.1 to 3%, respectively, based on the whole compsn.