The aim of the study was to assess the effect of selected vegetable oils on the representation of dietary fatty acids in the muscle of broiler cockerels. The experiment included three groups of one-day-old cockerels of ROSS 308 genotype, 15 individuals each. The feed mixture and drinking water were fed to the cockerels, ad libitum. In accordance with the technological instructions for the hybrid combination ROSS 308, BR1 was fed to chickens up to 9 days of age with the same nutrient and oil (soybean) composition for all three groups. From day 10 to day 28 of fattening the chicks were fed BR2 and from day 29 to day 35 BR3. The components and composition of the BR2 and BR3 feeds were identical; feed mixtures differed only in oil, soybean oil was added to Group 1 (SBO), rapeseed oil to Group 2 (RSO) and sunflower oil to Group 3 (SFO). Cockerels were fed until 35 days of age and then slaughtered. Breast and thigh muscles were collected from 10 individuals from each group to determine total fat in which individual fatty acid (FA) analysis was performed. Based on the obtained results, rapeseed oil can be clearly recommended for broiler chickens in feed mixtures, for the reasons that the cockerels from the RSO group showed the highest live weight (35 days of fattening), had the lowest feed conversion ratio, had an increased n-3 FAs content in the intramuscular fat (breast and thigh), and the narrowest n-3 : n-6 FAs ratio in the intramuscular fat (breast and thigh).