OBJECTIVE: To determine aetiology, clinical presentation and predictors of survival in Budd Chiari Syndrome patients. METHODS: The prospective observational study based on non-probability convenient sampling was conducted at the Sindh Institute of Urology and Transplantation (SIUT), Karachi, and comprised Budd Chiari Syndrome patients between January 2004 and December 2013. The patients were evaluated for onset of symptoms, causes, mode of presentation and predictors of survival. SPSS 20 was used for statistical analysis. RESULTS: Of the 25 patients, 16(64%) were males, and 16(64%) belonged to the paediatric age group. Overall age range was 2-50 years with a mean of 14.7 ± 12.41 years. Presentation was chronic in 14(56%) patients, acute in 10(40%) and acute on chronic in 1(4%). Commonest morphological abnormality involved was hepatic veins alone in 14(56%). Probable aetiologies were hypercoagulable states in 21(84%) patients, infections in 2(8%) and malignancy in 1(4%). Among hypercoagulable states, protein C deficiency was the commonest, affecting 9 (36%) patients. Seven (28%) patients died; acute 4 (16%) and chronic 3 (12%). Causes of death included sepsis 4 (16%), fulminant hepatic failure 1 (4%), gastrointestinal bleeding 1 (4%), and bleeding from liver biopsy site 1 (4%). Poor survival was associated with bilirubin > 5 mg/dl (p < 0.031), serum alanine transaminase > 40 U/L (p < 0.005), serum albumin < 2.8 g/dl (p < 0.008), Child-Turcotte-Pugh score > 10 (p < 0.001) and absence of varices (p < 0.025). Cox regression analysis failed to show any significant independent predictors of survival. CONCLUSION: Budd Chiari Syndrome affected young patients more frequently and was associated with high mortality. The commonest aetiology was hypercoagulable state. Survival was poor in patients with decompensated liver disease and those with an acute clinical presentation.