Polypropylene/wood flour composites were prepared by melt compounding. To improve their mechanical performance, the matrix polypropylene was modified with a specific nucleation agent based on an amide of dicarboxylic acid, which promotes crystallization predominantly in the beta-phase. The resulting material was used as a matrix for composites containing 10%, 20%, and 30% of wood flour. Uniform dispersion of the filler and improved interfacial adhesion was ensured by compatibilization with a small amount of maleic anhydride-grafted polypropylene. A beneficial effect of application of the nucleation agent together with a compatibilizer on the resulting mechanical behavior was shown. (c) 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 506-511, 2007