As more is learned about the possible health consequences of vitamin D deficiency, we are also discovering that many New Zealand children have less than adequate levels of the ""sunshine vitamin"". Parents and health professionals are equally confused by the variety of messages they are receiving. Risk of deficiency in children is probably greater if they attend daycare or pre-school, live in the south of the country, or have dark skin. Furthermore, evidence suggests there is a relationship between vitamin D status and history of respiratory illness and allergy. The aim of this study is to measure the vitamin D levels of pre-schoolers from around New Zealand and to gather information on the predictors of deficiency with the objective of creating an easily used risk assessment tool for health professionals in the community. It will also enable investigation of the potential link with respiratory illness and allergy.