We describe our experience with color Doppler ultrasonography (CDU) in the preoperative staging of pancreatic cancer and, particularly, in detecting the involvement of the portal-mesenteric trunk (PMT). Of the 54 patients studied, 43 (79.6%) underwent surgery and 11 (20.4%) did not because of evident infiltration of the PMT. Of the 43 patients operated on, the CDU study was normal in 8 cases (18.6%), abnormal in 33 (76.7%), and not possible in the remaining 2 cases (4.7%). Results of the CDU were confirmed intraoperatively in 39 cases (diagnostic accuracy, 95.1%). In only two cases (4.9%) did the CDU not show involvement of the PMT, which was, instead, demonstrated by intraoperative ultrasonography (false negatives). Of the 11 nonoperated patients, all showed morphological alterations at CDU, while only 7 showed hematic flow changes. The sensitivity of CDU was 94.2% and the specificity 100%. The positive predictive value was 100%; the negative predictive value, 75%. The results indicate that CDU may be the first imaging technique for preoperative assessment of PMT involvement in pancreatic cancer.