The wide use of operative and diagnostic laparoscopy has led to a greater use of the laparoscopic ultrasound (LUS) as a complementary procedure. A preliminary study was performed to evaluate the efficacy of LUS using a linear array laparoscopic probe characterized by double frequency, mechanical flexibility, and availability of Doppler analysis. LUS was performed in 36 patients with gastrointestinal neoplasms and compared with preoperative sonography, computed tomography, and with laparoscopy alone. LUS identified liver metastases with a sensitivity of 100% versus 60% for preoperative diagnostic means and laparoscopy. Nodal metastases were identified with a sensitivity of 96.1% and a specificity of 66.6%. Therapeutic planning was modified as result of LUS in 8 of 35 cases (22.9%). In patients with abdominal malignancy, LUS improves staging (cancer spread, nodal metastases, liver metastases), modifying therapeutic decisions. LUS represents a complementary, indispensable diagnostic method during laparoscopic surgery.