In this study, some 3-arylamino-5-[2-(substituted imidazol-1-yl or benzimidazol-1-yl)ethyl]-1,2,4-triazole derivatives were synthesised by reacting 3-(substituted imidazol-1-yl)propionyl hydrazides, with S-methyl-N'-arylisothiouronium iodide salts. Their structures were elucidated by IR,H-1-NMR and mass spectroscopic data and elemental analyses results. Antimicrobial activities of the compounds were observed against Staphylococcus aureus NRRL B-767, Micrococcus luteus NRRL B-4375, Escherichia coli B, Pseudomonas aeroginosa NRRL B-23 and the fungi Candida albicans and Candida glabrata by using the tube dilution technique. Remarkable activity was obtained. (C) 2000 Editions scientifiques et medicales Elsevier SAS.