The patent literature for dipeptidyl peptidase IV (DPP-IV) inhibitors for the period of January 2001 to May 2002 is reviewed. There has been increased interest in DPP-IV inhibitors since their potential for the treatment of diabetes was identified. This review will focus on reversible inhibitors of the enzyme, for which the primary interest has been for use in the treatment of Type II diabetes. The majority of the new chemical entities reported are dipeptide-like inhibitors that mimic the preferred substrates and the best of these display nanomolar activity. There have been fewer reports of non-peptide inhibitors suggesting that it is much more difficult to identify new classes of inhibitors. In addition to new chemical entities this review will cover new indications for DPP-IV inhibitors that have been identified using previously reported inhibitors as research tools.