Résumé/Abstract Treatment of 3-alkyl-2-(N-cyanoimino) thiazolidines with lithium aluminium hydride caused reductive cleavage of the imino double bond to afford 3-alkylthiazolidines, while diisobutylaluminium hydride reduction of 3-alkyl-and 3-sulfonyl derivatives resulted in the nitrile reduction or imino-nitrile bond cleavage to give 2-formyliminothiazolidines and/or 2-iminothiazolidines.