The objective of the study was to evaluate the effect of vaccenic acid addition to pig feed mixture on fatty acid content in pork. Thirty two pigs (Czech Landrace x Czech Large White) x line 48 were included into the experiment. Animals were divided intotwo groups ? control (V0) and experimental (V1) with vaccenic acid product (2kg/t of feed mixture, one month before the end of the fattening period). M.longissimus dorsi samples were taken 24 h post mortem. Vaccenic acid in pig diet significantly (P < 0.01) increased content of CLA (C18:2 (9,11) isomer). Significantly lower (P0.05). The decrease of total unsaturated fatty acids was also not significant. MUFA content was higher in V1 group compared to V0 group (P > 0.05). On the contrary, PUFA content was in V1 group lower. The n-6/n-3 PUFA ratio was not influenced by the diet ( P> 0.05).