The aim. Development of methods of quantitative determination of Cardiazol substance using high-performance liquid chromatography.Materials and methods. The method of high-performance liquid chromato-graphy (HPLC) was to determine of quantitative determination of Cardiazol substance ([3-Allil-4-(41-methoxyphenyl)-3H-thiazole-2-ylidene]-(32-trifluoro-methylphenyl)amine hydrobromide) using Shimadzu Nexera X2 LC -30AD (Shimad-zu, Japan). The acetonitrile of the HPLC grade (Sigma-Aldrich GmbH, Switzerland) was used in the work and other chemicals and solvents were of analytical grade. The test substance was diluted in acetonitrile at a final concentration of 400 μg/ml.Results and discussion. The method of quantitative determination of Cardiazol substance with the help of highly effective liquid chromatography is developed. The developed conditions of testing are selected experimentally. The following optimal conditions for the chromatographic distribution were found: column C8 (250 *4.6 mm; speed of the mobile phase 1 ml/min; thermostat temperature of the column 35 ° C; detecting wavelength 300 nm; holding time of the test compound is 13.9 min. Suitability of determination methods.The following optimal conditions for chromatographic separation were revealed: a C8 column (250*4.6 mm, a mobile phase speed of 1 ml/min, a column thermostat temperature of 35 °C, a detection wavelength of 300 nm. Under the proposed conditions, the retention time of the tested component is 13.9 minutes. The performance of the column was determined for its main indicators, such as the theoretical number of plates (over 65000) and the coefficient of symmetry (about 1.00). The method of quantitative determination was tested in accordance with the recommendations of the Ukrainian and European Pharmacopoeia. The proposed method meets all requirements. The method has been tested for the effects of various factors such as flow rate, the composition of the mobile phase and the temperature of the column thermostat. It is established that the influence of these factors is insignificant and does not affect the results obtained by this method.Conclusions. An analytical method for quantitative determination of Сardiazole substance with cardioprotective action has been developed on the basis of the high-performance liquid chromatography method. The conditions for chromatographic analysis (HPLC) were standardized. Requirements for the test "Checking the suitability of the chromatographic system" were established. The statistical processing of the results of the experiment shows that the relative uncertainty of the average result was within the permissible limits. The developed method for the determination of Сardiazole will be used for further study of substance as a component of various dosage forms