PURPOSEWilms tumor (WT) and neuroblastoma (NB) are the most common pediatric abdominal malignantneoplasms of the kidney and adrenal gland. Differentiating them from each other is essentialsince their treatments are different. Here, we aimed to show the diffusion characteristics ofWT and NB for differentiation.METHODSDiffusion-weighted imaging (DWI) of 17 histopathologically diagnosed lesions (10 NB and 7 WTin 8 female and 9 male patients) was evaluated retrospectively. The apparent diffusion coefficient(ADC) value for each tumor was calculated using region-of-interest (ROI) measurementsby two observers. The mean ADC values were compared, and receiver operating characteristics(ROC) curve analysis was performed. Intraclass correlation was evaluated for the reliability ofADC measurement.RESULTSThe mean ADC values measured by two observers were 0.787±0.09 ×10-3 mm2/s and 0.768±0.08×10-3 mm2/s for WT, and 0.524±0.16 ×10-3 mm2/s and 0.529±0.16 ×10-3 mm2/s for NB, respectively(P = 0.006 and P = 0.011). Intraclass correlation coefficient was 0.955. Utilizing ROC curve analysis,a cutoff ADC value of ≤0.645 ×10-3 mm2/s was obtained to differentiate NB from WT.CONCLUSIONADC values of NBs were significantly lower than WT with a perfect interobserver agreement. Wesuggest that DWI may have a role in differentiating the two tumors.