Asthma is a chronic inflammatory disease affecting nearly 300 million people worldwide, and 1,000 people die daily due to asthma. The prevalence of this disease is higher in developed countries. Studies have shown that obesity is an independent risk factor for asthma, and obese children are more at risk of developing asthma. These children experience more severe asthma and have a poorer response to treatment. On the other hand, there is a direct relationship between the reduction of vitamin D levels in early life and the development of asthma in the following years of life. Interestingly, obesity is a common risk factor for both asthma and vitamin D deficiency. Therefore, investigating the interaction between asthma, obesity, and vitamin D deficiency can play an important role in understanding the complex nature of asthma. The results of the study on the level of obesity and vitamin D in children with asthma, in addition to the fact that it can provide excellent information about the effect of obesity and vitamin D deficiency on children's asthma, can provide a basis for ecological studies to measure the correlation between the incidence of asthma in children and The amount of sunlight and food and cultural habits in different regions.