Background: Fecal biomarkers (FCP) may be characterized by a superior diagnostic sensitivity as they are highly organ specific. Fecal calprotectin meets the criteria of a laboratory parameter suitable for the assessment of inflammatory bowel disease. Objective: To evaluate FCP levels in both preterm and full-term infants after start feeding and its relationship with the type of feeding, birth weight, and other clinical and laboratory parameters. Patients and Methods: This study was carried out at the outpatient clinic of the Pediatric Department Zagazig University Hospitals on 88 infants during the period from October 2016 to October 2017. Results: FCP levels increased in 100% of infants involved in the study after feeding. FCP levels have a wide range of variation from 82 to 425 µg/g before feeding and from 174 to 692 µg/g after feeding. A significant negative correlation between FCP levels before and after feeding with birth weight especially in the full-term group. A higher percentage of increase was observed in breastfeeding and ranged from 64.76 to 91.31%, while formula-fed feeding ranged from 39.09 to 84.94%. Conclusion: FCP levels increased in all infants after feeding with a wide range of variations with no differences between infants born vaginally or with C-section. The FCP levels increased significantly with breastfeeding than formula-fed feeding.