The aim of this study was to evaluate the role of DW- MRI & ADC value in characterization of neck masses as well as prediction of tumor response to therapy. This study included 110 pediatric patients (63 males and 47 females with a mean age of (40.46±17.93) years) with head and neck mass. Routine MR imaging and diffusion weighted MR imaging were done on a 1.5-T MR unit using a single-shot echo-planar imaging (EPI) with a b factor of 0, 500 and 1000 s mm−2. The ADC value was calculated. The mean ADC values of the malignant tumors and benign masses were calculated. Results: there was highly statistical significant difference (P< 0.001**) between means of benign and malignant swellings on MRI with ADC findings, with mean ADC value of malignant tumors was 0.98±0.20 and that of benign tumors was 1.76±0.39. DWI is a simple, noninvasive and not time consuming imaging modality that if added to conventional MR imaging can increase sensitivity and specificity in differentiating between benign and malignant neck masses.