Аннотация:The results of long-term observational program of classical cepheid investigations carried out in Moscow from 1980th, are presented. The data base includes more than 75000 UBVRI photoelectric and CCD brightness measurements for more than 650 galactic Cepheids, and approximately 10000 precise measurements of radial velocities for 165 Northern Cepheids. Classical Cepheids as stars with the most reliable distance scale play an important role in all investigations of the structure and dynamics of the galactic disk. Being observed on 100 year time interval, more than 90% of cepheids show systematic period changes. New observations are necessary to improve cepheid period-luminosity relations by taking into account the difference in their evolutionary stages and misidentification of pulsation modes.