Maternal vitamin D deficiency  and childhood asthma and wheeze  are common health problems. Risk factors for low vitamin D levels include dark skin , and ethnic variations in the prevalence of asthma have previously been reported [4, 5]. Whilst it is known that rates of both circulating vitamin D levels and childhood asthma differ by ethnicity, to our knowledge, no UK study as previously investigating ethnic differences in their association with each other. Our aims were to quantify maternal vitamin D levels and the prevalence of asthma and wheeze in a bi-ethnic cohort of UK-born children, and to explore the relationship between them. This article is protected by copyright. All rights reserved.