Background: Asthma is the most common chronic disease in childhood. Several factors have been considered as the disease risk factors. The neonatal phototherapy has recently been recognized as the main childhood risk factor. The aim of this study was to evaluate the relationship between the neonatal phototherapy and childhood asthma.

Materials and Methods: This analytical case-control study was conducted on the asthmatic children with a history of neonatal icterus as the case group and those with no history of neonatal icterus as the control group with similar characteristics (age, gender, type of delivery and birth weight). Twenty-eight out of 200 subjects in the case and 34 in the control group had the inclusion criteria. Phototherapy and its duration were compared in the case and control groups. Data were analyzed using chi-square and t-test.

Results: Twenty-six (92.8%) subjects in the case group and 20 (58.8%) subjects in the control group had a past history of phototherapy (P=0.002). The mean number of days for neonatal phototherapy in the case and control groups was 4.9 and 3.2, respectively (P=0.001).

Conclusion: This study shows that neonatal phototherapy, as well as its duration, is an effective factor affecting childhood asthma. So, the phototherapy must be avoided except in rare situations with the least duration.