Different levels of beta-form crystallinity in isotactic polypropylene (IPP) were produced by blending a series of additives. X-ray diffraction analyses showed that the Kx values varied from 0 to 0.95. Indigosol Brown IRRD, Indigosol Red Violet IRH, Cibantine Orange HR, Indigosol Pink IR, Cibantine Blue 2B, Indigosol Golden Yellow IGK, and Indigosol Grey IBL were found to be effective beta-nucleators. The respective Kx values of the iPP samples containing the above seven beta-nucleators of 0.05 wt % are 0.54, 0.68, 0.82, 0.82, 0.86, 0.92, and 0.95. All the beta-nucleators possess fused benzene rings or heterocycles in their molecular structures. X-ray diffraction studies on them revealed a mutual character in that the strongest or the second-strongest reflections almost locate at the d-spacing of 2.83 Angstrom. The magnitude is about half of that of the beta-form crystallinity d-spacing (5.64 Angstrom). The beta-form level also depends an a number of factors under our control, such as the beta-nucleator concentration, cooling rate, crystallization temperature, and melt temperature. Polarizing microscope observations suggested that beta-spherulites possess a bright color and that their Maltese Crosses display some concentric banding of a rather spiky, jagged character. Their lamellae exhibit a correlated and dendritic structure seen by a scanning electron microscope.