The effects of an oregano and/or rosemary (Origanum vulgare L. and/or Rosmarinus officinalis L.) dietary supplementation to the diet of fattening pigs were investigated. Thirty-two grower-finisher pigs (45 kg) were divided into four dietary groups identified as: control diet (CTR); CTR+ 0.2% oregano (O); CTR + 0.2% rosemary(R), and CTR+ 0.1% oregano + 0.1% rosemary (OR). During the finishing period, all groups received a further supplementation of 0.5% of conjugated linoleic acids (CLA). Blood samples were collected after an adaptation period of 15 days to the new diet (T1) and at the end of the finishing period (T2) to evaluate antioxidant status (total antioxidant power and reactive oxygen metabolites) and immune responses (lymphocytic phenotyping and IgG levels). Pork meat samples were evaluated for glutathione peroxidase activity (GSHPx), total phenolic content and preference rating. A significant increase in B lymphocytes (CD79 + ) and a higher IgG level was observed in the R and O groups (P<0.05). Furthermore, there were significant effects of dietary supplementation on meat GSHPx activity and total phenolic contents (P<0.001 and P<0.005, respectively). Preference rating showed that pork derived from group R was the most preferred by the consumers.