Background: An important part in calcium and phosphorus balance, bone metabolism, and bone growth is played by the steroid hormone vitamin D. Vitamin D's impact on cancer, the immune system, cardiovascular disease, and glucose homeostasis has recently been revealed. The aim of this study aimed to assess blood 25-hydroxyvitamin D concentration in newborns with pneumonia and to correlate vitamin D with serum level of procalcitonin (PCT) and C-reactive protein (CRP) as a markers of acute inflammation. Patients and methods: This case-control study was carried out in NICU Paediatric Department at Zagazig University Hospital, during the period from March 2022 to August 2023. This study Including 30 neonates with pneumonia in addition to 30 healthy controls. Serum vitamin D, Procalcitionin, Complete Blood Count (CBC) and C-reactive protein (CRP) levels were measured for all participants. Results: There was a significant lower value of Serum 25 (OH) D and vitamin D in patients compared to control group. The cut off value of vitamin D in diagnosis neonatal pneumonia was <12 (ng/ml) with sensitivity 80.0% and specificity 90.0 and total accuracy 85.0%. When comparing the weight of neonatal in pneumonia group with control group regarding the weight, it was found a significant decrease in body weight in pneumonia group less than the healthy control. Conclusion: Vitamin D levels is associated with higher incidence of neonatal pneumonia. Vitamin D levels were significantly related to severity of pneumonia. Blood CRP was inversely associated with vitamin D in neonates with low 25(OH)D levels.