The aim of this population-based retrospective cohort study was to investigate the onset of urinary tract infection in newborns and the associated risks of childhood asthma. Children with neonatal UTI (n = 3,312) and randomly selected controls (n = 13,243) were enrolled for our analysis. We calculated the follow-up person-years for each participant from the index date until the diagnosis of asthma, the end of 2008, or withdrawal from the insurance system (because of death or loss to follow-up). Furthermore, we compared the risk of asthma between non-UTI and UTI cohorts by using Cox proportional hazards model analysis, the adjusted hazard ratio (aHR), and a 95 % confidence interval (95 % CI). The overall asthma incidence rate was found to be 1.53-fold significantly higher in the UTI cohort than in the non-UTI cohort (70.3 vs 45.8 per 1000 person-years). After we adjusted for potential risk factors, the overall risk of asthma remained higher in the UTI cohort (aHR = 1.47, 95 % CI = 1.35-1.59). The incidence rate was higher in boys than in girls. Overall, patients suffering from UTI may have a greater risk of developing asthma than patients without UTI. This nationwide retrospective cohort study demonstrates that neonatal UTI may increase the risk of childhood asthma.