Abstract Background The Ketogenic Diet (KD) is a high-fat, low-carbohydrate, and adequate-protein diet and a well-established treatment option for drug resistant childhood epilepsies. Neutrophils are important component of humans` innate phagocytic defense which usually arrive first at sites of infection and/or inflammation. Objectives The objective of this study was to assess the effect of ketosis induced by KD on neutrophils count. Methods This case control study was done in the Ketoclinic, Children’s Hospital, Ain Shams University, during the period of May 2018 till December 2019. It included 21 patients and 9 age and sex matched healthy children as a control group. Neutrophil counts were measured in both patients and controls both initially and after 6 months of KD usage. Results Although three patients reported increased incidence of infection after commencement of KD, the current study showed no significant change in the neutrophil count in studied patients compared to the controls after 6 months of KD. Conclusion KD has no effect on neutrophil number, however, further detailed studies for the full immunological profile including their function is needed to ensure that patients receiving this line of therapeutic nutrition aren`t susceptible to increased risk of infections.