Ultrasound is a non-invasive, available, low-cost modality and is free of side effects. The current study has been performed to assess the diagnostic accuracy of ultrasound compared to CT scan as a gold standard in the diagnosis of craniosynostosis. 44 infants (17 girls) under 1 year old, clinically suspected to have craniosynostosis, were first sonographically examined by a pediatric radiologist and were later referred to another pediatric radiologist to examine CT scan with 3D reconstructed images of skull as gold standard modality. The second radiologist was blinded to results of the ultrasound. Sensitivity, specificity, positive and negative predictive values of ultrasound versus CT scan were 96.9%, 100%, 100%, and 92.3%, respectively. The high specificity of ultrasound helps to correctly rule out craniosynostosis in clinically suspected cases and thus, can prevent unnecessary exposure of healthy infants to CT scan ionizing radiation.