The present study tested a hypothesis concerning a favourable effect of dietary fish oil on the tissue polyunsaturated fatty acid (PUFA) deposition, and on plasma lipid and cytokine profile. Thirty-two pigs divided into two groups of 16 animals each were fed for 70 days a diet with 2.5% of fish oil (F) and palm oil (P), respectively. The content of PUFA n-3 in the liver, muscle (m. quadriceps femoris), and visceral adipose tissue (VAT) of the F- and P-pigs was 530 and 129, 84 and 19, 1365 and 191 mg/100 g of the fresh tissue, respectively (differences between dietary groups were significant at P < 0.01 in all tissues). Dietary fish oil in comparison with palm oil decreased (P < 0.05) total plasma cholesterol, but also desirable high-density lipoprotein cholesterol, and had no effect (P > 0.05) both on low-density lipoprotein cholesterol and triacylglycerols. Moreover, dietary fish oil increased (P < 0.05) expression of the genes coding for not only anti-inflammatory cytokines IL-10 (P < 0.01) and TGF-β1 (P < 0.05), but also for pro-inflammatory cytokines IL-6 (P < 0.01), IL-12, and TNF-α (P < 0.05) in the VAT, and increased (P < 0.05) the expression of the IL6 gene in the liver. On the other hand, no significant differences (P > 0.05) between the F- and P-pigs in plasma levels of any tested cytokine were found out. It was concluded that an effect of dietary fish oil on tissue fatty acid deposition is undeniable, but its effects on plasma markers related to the risk of chronic degenerative diseases require further research.