Kors’ own research interests focus on the themes Cystic Fibrosis and development of other bronchusobstructive diseseases in young children. The studies crosslink basic mechanisms to clinical applications and long term developmental outcomes in children. In recent years, the prognosis of many of these disorders has greatly improved, making him especially focused on the long-term outcomes of his patients. He is convinced that improvement of long-term outcomes is based on improvement in treatment in childhood. In order to get a grip on the problems in adulthood, he initiated so-called life-course outpatient clinics in the Wilhelmina Children's Hospital, were pediatric and adult physicians closely collaborate in chronic patient care. He also conducts studies into disease development in healthy infants and children. For example, the Wheezing Illnesses Study Leidsche Rijn is a birth-cohort study in 3000 children into the development of chronic disease in relation to psychological and social well-being, in cross-collaboration with the Strategic Theme Dynamics of Youth of the Utrecht University. Starting from its own research experiences Kors stimulates interdisciplinary programs focusing on the life-long physical and mental effects of chronic diseases in childhood like ante- and perinatal damage, congenital abnormalities, severe inflammatory disorders and (post-)childhood cancer.