According to one embodiment of the present invention, a method for integrating client and server deduplication systems may be provided. In this method, a first hash set of a previous backup session may be received from a server. The first hash set may comprise a plurality of cryptographic values generated using a plurality of data blocks of a first data set of a client. A second hash set may be generated using a plurality of data blocks of a second data set of the client. A deduplicated data set may be generated by the client according to the first hash set and the second hash set and may comprise a plurality of non-redundant data blocks of the second data set. The second hash set and the deduplicated data set may be transmitted to the server.