Crystallization properties of polypropylene (PP) in PP/Ag composites were estimated from differential scanning calorimetry (DSC) and wide-angle x-ray diffraction studies. The effect of Ag powder and its surface modification with a titanate coupling agent on rates of nucleation and growth of crystallization, crystallite size distribution, and crystallinity was determined from crystallization exotherm peaks. Crystallinity and tensile properties such as modulus, yield strength, and breaking elongation decreased with Ag concentration. Linear correlations were obtained with tensile and crystallization parameters in both types of composites.