PURPOSE: To provide a grease compsn. which has a high retarding action at a high temp. against objects which are making relative movement and can withstand repeated use, by blending a thermoplastic resin and a thickener with an organopolysiloxane.

CONSTITUTION: A compsn. consists of 10W90pts.wt. organopolysiloxane, 90W 10pts.wt. thermoplastic resin having a softening point (according to a ring and ball method) of 50°C or above and 1W30pts.wt. thickener. The organopolysiloxane used as a base oil is a compd. of the formula (wherein R1 is OH, a monovalent hydrocarbon group; R2 is a monovalent hydrocarbon group; n is a positive number) and having a viscosity of 100,000W500,000cst at 25°C. Examples of the thermoplastic resins are pref. natural terpene resin and petroleum resins. The thickener is a compd. which can impart a desired viscosity to the blend of the organopolysiloxane and the thermoplastic resin and can stably keep the viscosity. Examples of such compds. are metallic soaps, fine fluororesin powder, phthalocyanine, silica, etc.