By using a commercial beta-nucleating agent (TMB-5) for polypropylene (PP), it was observed that high beta-crystal content in a compatibilized blend of polypropylene/polyamide-6 (labeled as Blend-03 in this work) can be achieved for samples prepared by compression moulding. As beta-PP possesses more superior impact strength then alpha-PP, and the beta to alpha transformation is an important mechanism of energy absorption for beta-PP, it is of obvious interest to understand the possibilities of beta to alpha transformation in beta-polypropylene/polyamide-6 blends. Tensile tests were performed at temperatures of 20, 30, 40, and 50 degrees C, and the occurrence of beta to alpha transformation was monitored by differential scanning calorimeter and wide angle X-ray diffraction measurements. It was observed that the beta to alpha transformation in Blend-03 could only be activated at elevated tensile testing temperatures. This was related to the increase in tensile elongation at break with the increase in tensile testing temperature. (c) 2007 Wiley Periodicals, Inc.