The present study suggests the method for determining the content of mediborol in oil solution using HPLC. The proposed method is characterized by high efficiency, good resolution and specificity. The accuracy is in the range of 98,44 to 102,05%. The method showed that the dependence of real content from observed content of mediborol in the concentration range16,00 – 24,00 mg/ml is linear with correlation coefficients of R² = 0,99964. The relative error of mediborol ranges from 0,81 to 0,94%. The parameters of the system were practically subjected to the influence of small changes in chromatographic conditions, except for the retention time and capacity factor of mediborol’s peak.