Our understanding of porcine nutrition and immunity has increased dramatically over the last two decades. For the vast majority of nutrients, researchers attempted to demonstrate the potential to improve immunity in pigs. The use of lipopolysaccharide to stimulate the immune system often was used to evaluate the influence of nutrition; however, all pathogens are not created equal and there is considerable variation within a single pathogen, let alone within a disease category. We need to learn more about how each antigen interferes with metabolism, and disease challenges are likely multi-factorial, which makes it challenging to plan for each disease-related scenario. Environmental regulations are becoming stricter and these regulations vary from country to country. Hence, some of the nutrients, which provided alternatives to antibiotic therapies, face more obstacles for practical, on-farm use. This chapter is not intended to review all nutrients, nor the complete immune response, but rather to provide select examples of nutrient strategies to boost immune function.