The growth of Cupriavidus eutrophus B-10646 and the synthesis of the polymer from oleic acid in different concentrations (5-50 g/L) were studied. The maximum yield of biomass (6.4-6.7 g/L) and the polymer content (64-71% of the weight of dry biomass) was obtained from 10-20 g/L of oleic acid after 48 hours of cultivation. In addition to 3-hydroxybutyrate, which is the dominant monomer (more than 98 mol.%), 3-hydroxyvalerate (0.7-1.7 mol.%) and 3-hydroxyhexanoate (0.1-0.4 mol.%) were identified in the polymer synthesized by bacteria. It was shown that as the concentration of oleic acid increased, both the weight-average (from 803 to 381 kDa) and the number average (from 292 to 94 kDa) molecular weight decreased but polydispersity of polymers increased (from 2.8 to 4.1).