Internally consistent distances to classical cepheids can be derived with considerable accuracy because they satisfy period-luminosity and period-colour relations. Studies of five cepheids that are members of galactic clusters have led to a revised period-colour relation and a new zero point for the period-luminosity relation. Distances have been computed for all cepheids given in recently published photoelectric surveys. The material can be regarded as complete to a distance of about 1500 pc.