Aim. The aim of present study was to conduct modelling of the virtual library of 4-aryl-5-oxo-4,5-dihydro[1,2,4]triazolo[4,3-a]quinazoline-8-carboxamides, to determine the most probable biological activity spectrum and the acute toxicity of studied compounds by PASS and GUSAR software, sort out the most perspective substances and develop preparative protocols for their synthesis. Methods. Using the PASS program computer prediction of the biological activity of 4-aryl-5-oxo-4,5-dihydro[1,2,4]triazolo[4,3-a]quinazoline-8-carboxamides has been performed. Prediction of the acute toxicity has been carried out by the GUSAR software. The structure of the compounds synthesized has been proven by elemental analysis and 1 H NMR spectroscopy data. Results. The synthesis of 4-aryl-5-oxo-4,5-dihydro[1,2,4]triazolo[4,3-a]quinazoline-8-carboxamides has been conducted starting from corresponding methyl 3-aryl-4-oxo-2-thioxo-1,2,3,4-tetrahydroquinazoline-7-carboxylates, which were converted into corresponding 3-aryl-2-hydrazino-4-oxo-3,4-dihydroquinazoline-7-carbohydrazides by treatment with hydrazine hydrate. Heating of these 2-hydrazinoquinazolin-4(3H)-ones with acetylacetone was resulted in 4-aryl-8-[(3,5-dimethyl-1H-pyrazol-1-yl)carbonyl]-1-methyl[1,2,4]triazolo[4,3-a]quinazolin-5(4H)-ones formation. Following substitution of pyrazole moiety by interaction of these compounds with primary amines led to destinated 4-aryl-5-oxo-4,5-dihydro[1,2,4]triazolo[4,3-a]quinazoline-8-carboxamides. The PASS program computer prediction of the biological activity of 4-aryl-5-oxo-4,5-dihydro[1,2,4]triazolo[4,3-a]quinazoline-8-carboxamides has allowed identifying the types of activity of studied compounds and sorting out the leaders with potential antineurotic activity, which are perspective for male reproductive and erectile dysfunction treatment. Prediction of the acute toxicity has been carried out by the GUSAR software, which allowed to refer them to slightly toxic (class 4) or practically nontoxic (class 5) substances. Conclusions. The obtained compounds are perspective objects for further investigations as slightly toxic (nontoxic) substances with potential antineurotic activity, which are perspective for male reproductive and erectile dysfunction treatment