Objectives: To evaluate the importance of diffusion-weighted MRI imaging (DWI) as a truthful marker for detection of rectal cancer tumor aggressiveness, by studying the relation between apparent diffusion coefficient (ADC) values of the tumors, MRI findings and pathological factors for prognosis. Methods: Between October 2017 and May 2019, the study included 80 patients have been proved to have carcinoma of the rectum by colonoscopic biopsy and histopathological assessment. All patients were assessed prior to surgery and neo-adjuvant therapy with standard MRI and diffusion weight images. Results: The mean ADC values are lower with poor prognostic factors for tumors with high CEA levels more than 5 ng/ml (P = 0.004), positive nodal disease (P = 0.0001), positive LVI invasion (P = 0.0001), with increasing T stage (P = 0.0001) and significantly lower among poorly differentiated tumors (P = 0.0341). There is also a significant positive correlation (r = 0.487; P = 0.0001) between ADC values and the distance from the tumor to the MRF. Conclusion: Our study suggests that quantitative measurement of ADC values can be used in preoperative assessment of degree of rectal cancer progression. ADC is capable of becoming a realistic imaging biomarker of tumor profile aggressiveness.