A study of ability to taste PTC was made on two groups of Tibetans representing Eastern and Central Tibet, and on an allied Mongoloid group, namely Ladakhis, inhabiting the northern outskirts of India bordering the western frontiers of Tibet. Noteworthy varia tions were observed in the frequency of the non-taster allele in the populations under study, reflecting the pattern of variation within the Tibetan racial complex. Frequencies of the non-taster gene reported in various Mongoloid populations are discussed and a general trend of variation within the Mongoloid ethnic complex hypothesised.