A programme of research on agricultural guanidine fungicides, represented by a complex mixture of several components (guazatine) and by a single compound (dedine[?] ), was carried out. The studies involved the synthesis of several guanidine derivatives and their characterization by spectroscopic methods such as carbon-13 NMR, MS. and FAB/MS. The synthetic routes have been described and different routes for the preparation of guazatine were also established.