Objective: To study the association between Vitamin D levels and the severity of asthma and the frequency of asthma exacerbations Design: cross sectional study Setting: tertiary care hospital Participants: A cross sectional study was undertaken in children with asthma attending Out-patient and In-patient Department of Paediatrics in K.V.G. Medical College, sullia. During the period 1st December 2018 to 30th November 2019. Results: Vitamin D deficiency was found in 54% of the asthmatic children and 17% had insufficient levels. Deficient Vitamin D levels were found in 41% of children with intermittent asthma, 58% of children with mild persistent asthma and 56 % of children with moderate persistent asthma where as insufficient levels of Vitamin D were found in 18% of the children with intermittent asthma, 16% with mild persistent asthma and 19% with moderate persistent asthma. Vitamin D deficiency/insufficiency was associated with increased frequency of exacerbations of asthma, longer duration of illness and also associated with higher AEC levels which are a marker of allergy and inflammation Conclusions: A high prevalence of Vitamin D deficiency and insufficiency was found in asthmatic children studied. On statistical analysis, no correlation was found between Vitamin D deficiency and severity of asthma. But Vitamin D deficiency was associated with increased frequency of exacerbations and was more common in children having illness of longer duration. Vitamin D deficiency was also associated with raised AEC levels thereby proving its immunomodulatory role.