This catalogue includes the Open Clusters of the supplement up to 1973 of the "Catalogue of Star Clusters and Associations" by Alter G., Ruprecht J., Vanysek V., Budapest 1970. The file "main.dat" contains the original data. For each cluster, the first line contains the running number (OCL) followed by various designations. The first five figures represent the galactic longitude (in 0.01degree), 'N' or 'S' for North or South galactic hemisphere, and galactic latitude (in 0.01degree). The second line contains the 1950 coordinates, the 50-yr precession, the galactic direction cosines and the position on the POSS charts. For each cluster a number of bibliographic records follow containing: YEAR: Year of the literature reference NAME: Author PUBLICATION: Reference AD: Angular diameter of the cluster in arc minutes DIST: Distance of the cluster (pc) LD: Linear diameter of the cluster (pc) N: Number of stars studied CI: Color index SP: Spectra P: Positions RV: Radial velocity (km/s) MT: Integrated magnitude NOTE: Notes The file "clusters" has been created from first and second lines; missing equatorial coordinates were derived from the galactic ones.