Atopic dermatitis and psoriasis are two common chronic inflammatory skin diseases. Both are multifactorial disorders caused by an interaction between genetic and environmental factors. Epidemiological studies estimated a high heritability of up to 80% for both diseases, indicating a major role of genetic susceptibility factors in disease development and progression. However, in contrast to monogenic disorders, complex diseases are not caused by single gene mutations, but are the result of a complicated network of numerous susceptibility loci, many of which exert additive or synergistic effects, but have only a small role when considered in isolation. Knowledge on the genetic architecture of atopic dermatitis and psoriasis is still incomplete, but major advances have been made in the past years, in particular through genome-wide association approaches.