Results are analysed of an experimental study of genetical determinants of some characteristics of man's colour perception in isolated populations. It has been shown that the characteristics in question can be divided into quantitative ones with continuous distribution within population, and qualitative ones with descrete distribution. Genetical analysis of one qualitative characteristic (perception of pure green colour) has been performed on the assumption that it is bimodally determined by two co-dominant genes G1 and G2 localized in the X-chromosome. Some data on how the described characteristics differ in various populations are presented.