The interest in CLA is centred on several biological properties that relate to health: anticarcinogenic, anti-obesity, anti-atherogenic and immunomodulatory functions. The amount of literature on CLA is growing at a phenomenal rate and today an evaluation of the influence of conjugated linoleic acid (CLA) on growth, carcass characteristics, meat quality and immune response in pigs is possible. No significant differences were observed on average daily gain, feed intake and a tendency for higher feed efficiency is reported. Limited effects on carcass characteristics and meat quality were observed. Backfat thickness was reduced in CLA fed pigs. Fatty acid composition of ham fat was significantly affected by dietary CLA. Higher saturated fatty acids, lower monounsaturated fatty acids and higher CLA content were observed in fat of CLA fed pigs. Dietary CLA had a positive effect on immune parameters of lactating sows and piglets. Feeding CLA increased sow colostrum IgG, IgA and IgM. Nursing piglets from CLA-fed sows had significantly higher serum lysozyme and IgG. These data suggest that conjugated linoleic acid have no, or limited, effects on growth performances, carcass characteristics and meat quality of pigs. The influence of CLA on fatty acid composition of adipose tissue may be very important from a technological point of view for the higher content of saturated fatty acids and from a nutritional point of view for the higher CLA content. CLA can affect cellular and Immoral responses to antigen challenge, affecting both adaptive and innate responses in pigs.