X-ray diffraction and true density measurement studies were carried out to investigate the effect of carbonization temperature (up to 2700 degrees C) on the extent of graphitization in Assam coking coal. With increasing carbonization temperature, the crystallite height (L(c)) and diameter (L(a)) and true density of the product increased considerably, while the interlayer spacing (d(0 0 2)) was reduced. The net result is that the extent of graphitization increases with increasing carbonization temperature. Carbonization at 2400 degrees C resulted in the formation of product having d(0 0 2) spacing and true density very close to those of pure graphite, while these properties of the 2700 degrees C carbonized product are somewhat better than those of pure graphite.