Primary hepatocellular carcinoma (HCC) is a common malignancy with a dismal prognosis; new modalities of treatment as alternatives to surgery have been developed for unresectable patients. The authors obtain baseline data for the natural history of HCC so that the efficacy of new treatments may be evaluated. A retrospective study of 157 untreated patients with tissue-proven or serodiagnosed HCC was conducted. Clinical characteristics including laboratory investigation, treatment received, survival from the time of diagnosis, and prognostic factors were evaluated. There were 129 men and 28 women (ratio, 4.6:1). Median age was 50.9 years (range, 14.1-85.3 years). The most common symptoms and signs were weight loss (68.2%), abdominal fullness (62.5%), abdominal pain (51.6%), hepatomegaly (73.7%), ascites (45.2%), and jaundice (40.6%). Eighteen percent had extrahepatic metastases of which the lungs were the most common site. Seventy percent were hepatitis B virus related. Overall median survival was 8.7 weeks after the time of diagnosis. Survivals by stages were: TNM II, 16.6 weeks; TNM III, 7.3 weeks; TNM IVA, 9.7 weeks; TNM IVB, 7.6 weeks; Okuda II, 10.7 weeks; and Okuda III, 7.3 weeks. Multivariate analysis revealed serum total bilirubin and albumin as independent prognostic factors of survival. Common causes of death were upper gastrointestinal hemorrhage (34.1%), cancer-related causes (cachexia, HCC rupture, metastatic disease, 31.8%), and hepatic failure (25.0%). Patients with HCC were diagnosed at late stages of their disease and the advanced nature of the tumor precluded effective therapy. Earlier tumor detection at a time when patients are better candidates for treatment may be aided by an active surveillance program of high risk groups.