Background: The base of the skull is a relatively common site for neoplasms. and their imaging features can overlap, so that the correct diagnosis decision has sometimes been made very difficult by routine magnetic resonance imaging (MRI), which can always be insufficient. The primary purpose of this study was to evaluate the feasibility of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) value measurement in distinguishing mass lesions at the skull base in adults Patients and methods: Between April 2020 and June 2021, a prospective study was conducted at the Department of Radiodiagnosis, University Hospitals of Zagazig, involving 45 patients clinically suspected of having skull base neoplasms diagnosed by CT. Our results were linked to histopathologic findings in all patients Results: Our study included 23 benign neoplastic lesions and 22 cases were malignant neoplastic lesions,The highest mean ADC value for malignant tumors was 1.15± 0.22 x 10-3 mm2/s, while the highest ADC value for benign tumors was 1.71 x 10-3 mm2/s, It was found that a cut of 1.2 x 10-3 mm2/s between benign and malignant lesions with an accuracy of 95.56%, a sensitivity of 90.91%, a specificity of 100%, a positive predictive value (PPV) of 100%, and a negative predictive value (NPV) of 92% at an AUC of 0.901 Conclusions: The DWI and ADC value are non-invasive, quantitative methods for detecting the natural skull base neoplasms