The present paper illustrates the results of the study on chromatographic behavior and optimization of some parameters of the method of quantitative determination of bornyl acetate and isobornyl acetate diastereomers under the conditions of reversed-phase high- performance liquid chromatography. Chromatography was performed with HPLC platform Agilent 1200 with diode-matrix detector and a column Agilent Zorbax XDB, Extend-C18. Detection of the studied analytes was performed at a wavelength of 210 nm. Determinationof the concentration of bornyl acetate isomers was carried out in mixture with other components of the Abiessibirica essential oil in chromatographic systems with mobile phases of acetonitrile-water or isopropyl alcohol-water. The range of analyte concentrations in a sample was varied from 2 to 430 mg/ml for bornyl acetate and from 2 to 950 mg/ml for isobornyl acetate. It is stated that in a chromatographic system with a mobile phase, based on acetonitrile, the peaks of the studied components have an asymmetric shape, and the retention times of analytes increase with the decrease of their concentrations in a sample. In a chromatographic system with isopropyl alcohol the asymmetry of the bornyl acetate peak disappears, the width decreases and the retention time stabilizes. For isobornyl acetate a peak width also decreases, its asymmetry is preserved, but at the same time, the asymmetry coefficient takes on permitted values (less than 2). Calibration charts for the mentioned compounds in the used eluents are linear throughout the studiedconcentration range with correlation coefficients of R2>0.998. Thus, the conducted researches allow to recommend the reversed-phaseHPLC variant for the separate quantitative determination of bornyl acetate and isobornyl acetate in the pine oil samples.