Introduction. Diuretic drugs occupy large niche in the pharmaceutical market due to the wide range of applications (reduction of edema in heart and vascular disease, kidney disease, decreasing the pressure, removing poisoning toxins). 1,2,4-triazole derivatives have proven themselves as promising compounds with diuretic, analgesic, antimicrobial activity. But still derivatives of 2-((4-amino-5-R-4H-1,2,4-triazol-3-yl)thio)acetohydrazides are studied insufficiently. The aim was to study the diuretic activity of 2-((4-amino-5-R-4H-1,2,4-triazoles-3-yl)thio)acetohydrazides and to establish some dependence between structure and action. Materials and methods. To establish the influence of the compounds on the excretory renal function we used well-known method by E. B. Berkhin. In each series we used 7 rats which were kept at a constant diet with free access to water. The animals were injected intragastrically with the substance in the form of an aqueous suspension stabilized by Tween-80 in a dose of 1/10 LD50, drinking water was administered after the 30 minutes at the rate of 5 ml per100 g of body weight. The urine was collected after 2 and 4 hours of the experiment. Results. Introduction of the 2-chlor-6-fluorbenzyliden, 3-nitrobenzyliden, 4-hydroxybenzyliden substituents in the 2-((4-amino-5-(thiophene-2-ylmethyl)-4H-1,2,4-triazole-3-yl)thio)acetohydrazide leads to the appearance of diuretic activity. Several compounds did not exhibit the diuretic activity. Introduction of 2,3-dimethoxybenzyliden, 2-brombenzyliden, 4-dimethylaminobenzyliden, 5-nitrofuran-2-ylmethylen radicals in the molecule of 2-((4-amino-5-(thiophene-2-ylmethyl)-4H-1,2,4-triazoles-3-yl)thio)acetohydrazide leads to the antidiuretic effect. Replacing of the thiophene-2-ylmethyl substituent on the 2-methylfuran-3-yl in 5th position of the triazole cycle increases the diuretic effect. Conclusions. We studied the diuretic activity of 20 new compounds of 2-((4-amino-5-R-4H-1,2,4-triazole-3-yl)thio)acetohydrazides. The synthesized compounds show moderate diuretic activity. The dependence between structure and action was found.