Background: Systemic inflammatory response syndrome (SIRS) is a systemic illness brought on by an infectious pathogen entering the body and causing production of inflammatory mediators. The purpose of this study was to investigate the use of transcranial Doppler ultrasound (TCD) in the detection of sepsis in children. Methods: This case control study was carried out in the Department of Pediatrics in Zagazig University Hospital on 24 septic children and 24 non septic. Results: Our study found no significant difference in Middle Cerebral Artery (MCA) peak systolic velocity (PSV) between septic patients and controls. However, we observed significantly lower pulsatility index (PI) and resistance index (RI) in the septic group. Similar to MCA findings, anterior Cerebral Artery (ACA) measurements showed significantly lower PI and RI in septic patients, with a slightly higher PSV. The lower PI and RI in our study might indicate decreased cerebrovascular resistance, possibly due to the inflammatory effects of sepsis on cerebral autoregulation. In our study, MCA_PI and MCA_RI showed strong negative correlations with heart rate, respiratory rate, and temperature, and strong positive correlations with blood pressure. This suggests that as sepsis severity increases (indicated by higher heart rate, respiratory rate, and temperature, and lower blood pressure), cerebral blood flow becomes less pulsatile and resistant. Conclusion: Our study demonstrated that TCD can detect significant changes in cerebral hemodynamics in children with sepsis.