IMMUNOGENETICS is the branch of medical genetics that explores the relationship between the immune system and genetics. Autoimmune diseases, such as type 1 diabetes, are complex genetic traits which result from defects in the immune system. Identification of genes defining the immune defects may identify new target genes for therapeutic approaches. Alternatively, genetic variations can also help to define the immunological pathway leading to disease. 

Immunology deals with the biological and biochemical basis for the body's defense against germs (such as bacteria, viruses, and fungi), as well as against foreign agents such as biological toxins and environmental pollutants, and failures and malfunctions of these defense mechanisms. Apart from these external effects on the organism, there are also defense reactions regarding the body's own cells, e.g. in the scope of the bodily reactions on cancer and the lacking reaction of a body on healthy cells in the scope of an immune-mediated disease. Hence, immunology is a sub-category of biology.

The term immunogenetics comprises all processes of an organism, which are, on the one hand, controlled and influenced by the genes of the organism, and are, on the other hand, significant with regard to the immunological defense reactions of the organism.