Aim: The aim of the present study is to evaluate the Procalcitonin Serum Levels inChildren Younger than Five Years Old with Urinary Tract Infection. Methods: This case-control study was done in the Department of Paediatrics, Government Medical College, Bettiah, West Champaran, Bihar, India from January 2019 to November 2019, The 100 (50 cases and 50 controls) children less than 5 years of age were included in this study. The children in the case group suffered from UTI based on a positive urinary culture test. They also were undergone VCUG and accordingly were divided into two groups: having VUR and not having VUR. Their serum levels of PCT weremeasured before starting antibiotic therapy usingthe chemiluminiscence immunoassay (CLIA).They (The control group),had negativeresults for both urine culture (UTI) and urinary analysis tests and the serum levels of PCT were measured for them. In both groups children under 5 years without any genetic diseases and chronic kidney disease, were included in the study. Results: Of the samples, 70 childrens (70%) were female. The median age of the samples was 22.5 months with an interquartile range between 10.5 and 35.5 months. Although, 70% of them had no vesicoureteral reflux, 20% and 10% of the samples suffered from severe unilateral VUR and sever bilateral vesicoureteral reflux, respectively. The VCUG and the serum status of PCT were compared between the groups. Accordingly, both the evaluation methods diagnosed 40 children to be healthy, while 90% of children with VUR positive simultaneously were PCT positive. The odds of one positive and two positive for one way 1.875 (P=0.011) times and 1.126(P=0.873) times were higher than the group without reflux. However the odds of 4 positive for one way 0.289 (P=0.2) times was lower than control group. Considering the number of cases, we rely only on descriptive statistics for other groups. According to our findings, 60% of the samples were positive with regard to the level of serum PCT. One-half of those samples (32 people) who was diagnosed to be healthy using VCUG had a normal level of serum PCT. The kappa score for the level of serum PCT was 0.2 (P < 0.0001). Conclusion: No significant relationship exists between vesicoureteral reflux and the serum level of PCT.