Objective: Our aim was to determine the contribution of diffusion weighted MRI (DWI) to abdominal MRI in detecting peritoneal implantsin patients with oncologic diagnosis. Materials and methods: Thirty-five patients operated for a malignant tumor and one patient for unknown primary malignant tumor wereenrolled in this prospective, observational study. Thirty-six oncology patients underwent abdominal and pelvic MRI, diffusion weighted MRIwith b value of 0-500-1000 s/mm2 . All MRI images were independently evaluated by two radiologists. Peritoneal implants were dividedinto five categories (0-0,5cm; 0,5-1cm; 1-2cm; 2-3cm and larger than 3cm ) according to lesion sizes. Nine patients results were comparedwith surgery or laparotomy. Remaining 27 patients were evaluated with follow-up MRI or CT at a varying time between 2 and 12 monthsfrom the initial MRI, and moreover they were also evaluated with laboratory values and clinical outcomes at the 12 to 36th month fromthe initial MRI. Results: Radiologist 1 detected 78 lesions with MRI, 136 lesions with DWI and 110 lesions with MRI+DWI. Radiologist 2 detected 89 lesionswith MRI, 125 lesions with DWI and 113 lesions with MRI+DWI. Peritoneal carcinomatosis was confirmed in 4 patients and 9 patientswere negative for carcinomatosis with all imaging modalities. On a patient-based analysis, sensitivity and specificity for radiologist 1 wererespectively 92%, 100% for MRI and 96%, 100% for MRI+DWI. Also for the radiologist 2 overall sensitivity and specificity of MRI and MRI+DWIwere similar to the radiologist 1.Conclusion: In our study we found that the sensitivity for contrast enhanced MRI+DWI was higher than MRI.