For 104 consecutive patients with hepatocellular carcinoma (HCC) with portal tumor thrombus (PTT) seen in the past nine years, prognostic factors were analyzed retrospectively using Cox's multivariate analysis. There was a significant difference in survival rate with hepatic functional reserve (Child classification, P = 0.005), type of treatment (surgical vs non-surgical treatment, P = 0.009) and PTT grade (P = 0.04). The survival rates for patients with Child's A (n 49) or Child's B (n 55) were 60.8 vs 20.0% at one year, 41.6 vs 9.1% at two years and 35.4 vs 5.5% at three years. The survival rates of patients with surgical (n 32) and non-surgical (n 72) therapy were 71.7 vs 25.0% at one year, 58.5 vs 9.4% at two years and 53.6 vs 4.7% at three years. Among patients with PTT grades in the third or lower order branch (Vp1, n 29), the second order branch (Vp2, n 32) and the first or portal vein trunk (Vp3, n 43), the one-year, two-year and three-year survival rates were 61.6, 43.8 and 20.9%; 47.1, 27.5 and 6.2% and 42.8, 27.5 and 0%, respectively. When analysis was focused on 32 patients with Child's A and PTT (Vp1 plus Vp2) with respect to treatment, the survival rates in the surgical (n 22) and nonsurgical (n 10) groups were 86.1 vs 70.0% at one year, 71.5 vs 30.0% at two years and 64.3 vs 20.0% at three years (P < 0.05), respectively. In HCC patients with PTT, surgery seems to be indicated where hepatic function is well preserved and the PTT is localized in a peripheral portal branch.