Iron is a crucial element for living organisms in terms of oxygen transport, hematopoiesis, enzymatic activity, mitochondrial respiratory chain function, and also immune system function. The human being has evolved a mechanism to regulate body iron. Dysregulation of iron metabolism can lead to oxidative stress, a condition in which the levels of reactive oxygen species (ROS) exceed the antioxidant defense capacity of the body, contributing to the pathogenesis of numerous diseases. The essential trace element iron regulates a wide range of biological processes in virtually all living organisms. Because both iron deficiency and iron overload can lead to various pathological conditions, iron homeostasis is tightly regulated, and understanding this complex process will help pave the way to developing new therapeutic strategies for inflammatory disease. In recent years, significant progress has been made with respect to elucidating the roles of iron and iron-related genes in the development and maintenance of the immune system.