UVB radiation stimulates the production of vitamin D and also has immunosuppressive effects. Vitamin D is also known to alter immunological function. Thus, a relevant question is whether vitamin D is a mediator of the immunological effects of UVB. In this issue, Schwarz et al. have addressed this issue and have concluded that although vitamin D has similar effects to UVB on the immune system, UVB-induced immunosuppression can be achieved without the requirement for vitamin D action.