We performed a comparison between the diagnostic value of F-18-FDG PET-CT and WB-MRI/DWIBS for detecting nodal and extra-nodal lymphomatous infiltrates. Thirty two patients with pathologically proven lymphoma (HL or NHL) underwent both F-18-FDG PET-CT and WB-MRI/DWIBS, to detect nodal and extra-nodal lymphomatous infiltration. Both F-18-FDG PET-CT and WB-MRI/DWIBS were independently interpreted using visual (qualitative) and quantitative analysis in the term of SUV max and ADC mean respectively. Using pathological data and/or combined clinical / radiological follow up as a reference standard, Sensitivity, specificity, PPV, NPV and overall accuracy were estimated for both techniques. F-18 FDG PET-CT demonstrated clearly higher parameters than WB-MRI/DWIBS. With the latter one showed a limited superiority in the context of bone marrow assessment. F-18 FDG PET-CT is better than WB-MRI/DWIBS in evaluation of lymphomas. The latter one may play a complementary role especially in assessment of BM infiltration.