Abstract: Technologies are described herein for providing efficient backup of multiple versions of a data file using data de-duplication. A CDP module copies blocks of data of a specific block size from a current version of the data file to a master file maintained in a backup location for the data file. Only blocks of data not matching a unique data block already in the master file are copied. The CDP module then creates an anterior file in the backup location for the current version of the data file containing an ordered list of references to the unique data blocks in the master file. The order of the list of references is based on the order of occurrence of each unique data block in the modified version of the data file. Finally, the CDP module creates a posterior file in the backup location for the current version of the data file containing any remaining block of data in the data file that is less than the specific block size.