Background: Transurethral resection of bladder tumor ) TURBT) is the common technique used in the management of non-muscle-invasive bladder cancer (NMIBC). Diffusion weighted magnetic resonance imaging (DWI) is used to assess several urinary tract pathologies. Aim of work: To correlate between the findings of DWI results and biopsy results of 2nd look TURBT in NMIBC and to correlate between DWI and conventional MRI in NMIBC before second look cystoscopy. Subjects and methods: A cross-sectional study conducted at the department of Urology, Zagazig university hospitals during the period from December 2018 till December 2019. The study included 24 patients with NMIBC underwent 2nd look TURBT with preoperative imaging with conventional and DWI on pelvis. All studied subjects were preoperatively clinically evaluated by gathering history and doing examination, pelvi -abdominal sonography, MRI including DWI and routine pre-operative laboratory investigations. Second look cystoscopy, biopsy and pathologic evaluation were done. Results: DWI had higher sensitivity, specificity, accuracy than conventional MRI in pathologic correlation with histological specimen, which were (100% VS 66.6%) sensitivity, (92.8% VS 50%) specificity and (96.8% VS 56.25%) accuracy for DWI and conventional MRI, respectively in the detection of bladder carcinoma. Our results showed high sensitivity of DWI for identifying the residual of bladder cancer after 1ry TURBT. There was a significant correlation between clinical staging by DWI and pathological staging. Conclusion: DWI could represent a beneficial tool for the best choice of patients before a second TURBT. Till now it cannot replace the gold standard second look cystoscopy with histopathology assessment.