Early Portal Vein thrombosis (PVT) represents a serious complication of liver transplantation (OLTx). Its incidence varies from 2.1% to 26%. From October 1997 through January 2004, 243 OLTx were performed in 215 pediatric patients (pts) at “Ospedali Riuniti di Bergamo”. Among the 215 primary grafts 154 were left lateral segments from in situ split (146), ex situ split (2) or reduced size (6) procedures and represent the subject for this report. We retrospectively analyze the incidence and the outcome of early (occurring during index hospitalization) PVT in this group. All the left lateral segment grafts included the celiac trunk, the left portal branch, the left hepatic vein and the left hepatic duct. A daily Doppler US scan was performed in all patients during the first week after transplantation. Early PVT occurred in 14 Pts (6.5%). There were 10 males and 4 females with a median age of 0.76 years (range 0.22-10.84). Median follow up was 360 days (3-2090 d). The main indication for the first transplantation was Biliary Atresia 10 pts (71.4%), followed by Byler’s disease 2 pts (14.2%), Cryptogenetic cirrhosis (7.1%). 3 of them (21,4%) underwent retransplantation, 3 (21,4%) had a surgical revision of the anastomosis, 2 (14,2%) pts are currently under beta blockers therapy to prevent variceal bleeding, one (7,1%) underwent a late meso-caval shunt after a failed percutaneous angioplasty and stenting. In the 5 (35,7%) remaining patients Doppler ultrasound showed a spontaneous recanalization of the portal vein. 4 pts (28.5) died, 2 after retransplantation, (one for veno-enteric fistula, one for sovra-hepatic vein thrombosis), one during retransplantation of intra-operative bleeding, one for multi organ failure. To date 12 pts (70,5%) are alive with an actuarial survival at 1 yr and 5 yr of 71,4% , the graft survival at 1 yr and 5 yr of 64,3%. PVT may represent a major problem after pediatric OLT with left lateral segmental grafts. Prompt detection and aggressive sural treatment in selected cases are required to limit the related mortality and graft loss.