Cephalic index is an important parameter in evaluating racial and gender differences. A large body of evidence shows a clear racial variation in cephalic index. Therefore detailed knowledge of the population specific data on biometric features of the cranium is important in the study and comparison of the crania of populations from different racial backgrounds, assessing growth and development of an individual and in the diagnosis of any abnormalities of cranial size and shape. Despite its' significance, little is known concerning the cranial morphometry in Sri Lankans. Hence, the present study was undertaken to establish the cranial indices and head shapes in an adult Sri Lankan population. A total of 400 subjects with an age span of 20-23 years were included in the study. The cranial length, breadth and auricular head height of the subjects were recorded using a digital sliding caliper and Todd's head spanner. The horizontal, vertical and transverse cephalic indices were calculated using external dimensions of the skulls. There were significant gender differences in all principal cranial dimensions. The mean horizontal, vertical and transverse cephalic indices were 78.54, 78.68 and 100.52 respectively. The predominant cephalic phenotype of the study subjects were brachycephalic, hypsicephalic and acrocephalic. Among males dolicocephalics and among females brachycephalics dominated. The results of this study highlight the racial and gender differences in cranial morphometry and cephalic indices in an adult Sri Lankan population. The data will be of immense use in clinical, medico-legal, anthropological and archeological scenarios.