Abstract: Spherical polyolefin (or modified polyolefin) powders having high bulk density, narrow particle size distribution and good powder flowability are prepared by cooling a polyolefin solution comprising a solvent and nonsolvent for the polyolefin and containing a small amount of an inorganic compound and, if desired, water. The polyolefin powders are suitable for powder coating. Suitable solvents are hydrocarbons, such as hexane, heptane, etc., and a mixture of hydrocarbon and nonsolvent for polyolefin such as methyl alcohol, ethyl alcohol, isopropyl alcohol, etc. The ratio of a hydrocarbon/nonsolvent is 95/5 - 30/70, preferably 90/10 - 50/50. Suitable inorganic compounds are phosphoric acid, sulfuric acid, sulfurous acid, hydrochloric acid, sodium hydroxide, potassium hydroxide, ammonium hydroxide, inorganic salts thereof, etc. and the most preferable inorganic compound is phosphoric acid.