In Sweden a system for colour description has been developed (NCS) which is based on the Opponent Colour Theory of perceptual organ-ization. The principles and the assumptions of the theoretical mo-del is described, as well as some aspects of its reliability and validity. The NCS-system with its connected colour-atlas will offer new possibilities for solving many practical problems about colours. The development process has generated many ideas for further studies of which the first ones on the research program are mentioned. Of already performed investigations two are referred: One is a study on the relation between dimensions of meaning and perceptive colour parameters. The second is studying the perceived meanings of exter-ior colours in architecture.