An experiment was conducted to determine the effects of altering the omega-6 (n-6) to omega-3 (n-3) fatty acid (FA) ratio in sow diets on the immune responses of their off spring post-weaning. Piglets were subjected to an immune challenge by injecting lipopolysaccharide (LPS), a component of gram-negative bacteria which triggers an immune response. Weanling pigs produced from sows consuming different n-6:n-3 FA ratios respond differently to an LPS induced immune challenge. This allows us to conclude that the FA profile of a sows diet may affect the response of her offspring to immune challenges which occur regularly at the time of weaning.