Recently, introduction of more aggressive surgical treatment and intraperitoneal chemotherapy appears to significantly increase the overall survival rate for these patients. A detailed preoperative assessment of peritoneal carcinomatosis could be very challenging in the field of imaging, but a new aggressive surgical approach requires an accurate preoperative assessment of the disease. Cross-imaging using CT and MRI with diffusion-weighted (DW) sequences is important for appropriate management of patients with peritoneal carcinomatosis. Appreciation of the spectrum of diagnostic patterns and pitfalls as well as different sites of involvement of peritoneal carcinomatosis using CT and DWI is crucial for appropriate surgical treatment. The aims of the lecture are to underline the role of 64 MDCT and DWI 3 T MRI in the evaluation of Peritoneal Metastases (PMs) in patients undergoing peritonectomy and hypertermic intraperitoneal chemotherapy (HIPEC), to understand advantages and drawbacks of each diagnostic imaging technique and to address which particular abdominal areas are the most important and crucial to evaluate in order to exclude the presence of PMs for a right selection of patients that must be surgically treated by HIPEC. 