A prospective study was conducted to compare the results of long-term endoscopic variceal sclerotherapy in patients with different aetiologies of portal hypertension. A total of 404 consecutive patients were included. There were 234 patients with hepatic cirrhosis, 83 with non-cirrhotic portal fibrosis (NCPF) and 87 with extrahepatic portal venous obstruction (EHO). The mean follow-up for patients with cirrhosis, NCPF and EHO was 25, 37 and 28 months. A total of 73 (31%) patients with cirrhosis, 19 (23%) with NCPF and 10 (11.5%) with EHO rebled (P less than 0.05) on follow-up, prior to eradication of varices. Irrespective of the aetiology, 40 (17%) patients of Child's A class, 42 (33%) of Child's B and 20 (50%) of Child's C class rebled (P less than 0.01). The median bleeding free period (BFP) was longer (P less than 0.05) in patients with EHO than in cirrhotics. Patients in Child's A class had significantly longer BFP than those in Child's B, and the latter had a longer BFP than those in Child's C class (P less than 0.01). The probability of 7-year survival was also better with EHO (97.5%) and NCPF (73.6%) than cirrhotics (41%). Survivals in patients with EHO and NCPF were comparable (P less than 0.1). Similarly 7-year survival irrespective of aetiology in Child's A patients (90.7%) was longer than in Child's B (28.8%), and longer in Child's B than Child's C patients (0%). Success of eradication was greater (P less than 0.05) in EHO (92%) and NCPF (87%) than cirrhotic patients (75%).(ABSTRACT TRUNCATED AT 250 WORDS)