The invention relates to a method for merging data sets of a data base with data sets of a data base of a data management system. To allow merging without losing relevant data, it is proposed to determine one data set as a merging basis, match data from the data bases to identify matching data sets, create a list of matching data sets, determine data sets within the list as merging partners, and merging the merge partners with the merging basis into a single data set.