<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>Differentiating esthesioneuroblastoma (ENB) from other sinonasal tumors is difficult by MRI. We tested whether diffusion weighted imaging (DWI) could distinguish ENB from other sinonasal tumors.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Hundred forty‐six patients underwent sinonasal MRI, 75 with technically successful DWI. Pathology: 18 ENB (24%), 34 (45%) other malignant tumors, and 23 (31%) benign lesions. Apparent diffusion coefficients (ADCs) were calculated.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Average ADC and normalized ADC of ENB (1.22 × 10<jats:sup>−3</jats:sup> ± 0.28 mm<jats:sup>2</jats:sup>/s and 1.55 ± 0.36, respectively) were higher than other malignancies (0.98 × 10<jats:sup>−3</jats:sup> ± 0.18 mm<jats:sup>2</jats:sup>/s and 1.31 ± 0.29, <jats:italic>P</jats:italic> = .002 and <jats:italic>P</jats:italic> = .034) and lower than benign disease (1.92 × 10<jats:sup>−3</jats:sup> ± 0.33 mm<jats:sup>2</jats:sup>/s and 2.44 ± 0.50, <jats:italic>P</jats:italic> < .0001). ADC differentiated ENB from benign disease with 91% sensitivity and 83% specificity. An ADC cutoff of 1.1 × 10<jats:sup>−3</jats:sup> mm<jats:sup>2</jats:sup>/s differentiated other malignancies from ENB with 72% sensitivity and 85% specificity.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>DWI is useful in distinguishing ENB from other sinonasal disease.</jats:p></jats:sec>