With the objective of verifying the influence of oleic acid as a nutritional supplement in the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by Ralstonia eutropha, cultures were established with 0.3 g oleic acid l(-1) and without this supplement, in 30 g inverted sugar l(-1) and 1 g propionic acid l(-1). The use of this supplement increased the accumulation of polymer from 18.3% to 28.3% (w/w) although the mass of 3-hydroxyvalerate in the polymer remained constant for both cultures.