<title>Abstract</title> <p> <bold>Background:</bold> Wilms tumor (WT) is a heterogeneous pediatric renal malignancy. Invasive procedures to establish histology prior to pre-operative treatment are not recommended by the International Society of Pediatric (SIOP) Oncology Renal Tumor Study Group, yet different tissue components are associated with different responses to therapy (SIOP Umbrella protocol). Intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) may improve subtype differentiation before surgery as a noninvasive radiographic biomarker by capturing both diffusion and perfusion characteristics, as opposed to the conventionally-used apparent diffusion coefficient (ADC). The objective of this study is to evaluate the discriminative performance of IVIM MRI in differentiating WT subtypes. IVIM provides quantitative parameters that disentangle the diffusion coefficient (D), incoherent blood flow (pseudodiffusion, D*) and perfusion fraction (f). <bold>Materials and methods:</bold> This retrospective study included thirthy children with WT. Standardized 1.5T MRI with 10-b-value diffusion weighted imaging (DWI) was performed. IVIM parameters were estimatedusing a self-supervised implicit neural representations network and were correlated with histopathology via a patient-specific 3D-printed cutting guide. Statistical analyses included mixed models, receiver operating curve analysis, and logistic regression. <bold>Results:</bold> Thirty lesions were MRI–histopathology correlated on slice-level. Significant subtype differences were observed for D* stromal versus epithelial (p = 0.024), regressive tumors (p = 0.031) and mixed WT tumors (p = 0.043). ADC showed no significant subtype differences. <bold>Conclusions:</bold> Direct MRI–histopathology correlation enabled differentiation between stromal subtype andepithelial, mixed and regressive subtype on macroscopic slice level using D*. Future research should focus on data addition and optimizing equal representation of different tissue types. </p>