To investigate mortality in adult patients with epilepsy in Taiwan, a total of 263 patients with epilepsy aged > or = 17 years, referred to the outpatient epilepsy clinic between 1 Jan and 31 December 1991, were prospectively enrolled and followed up until 31 December 2000. A total of 32 deaths were reported. Overall case-fatality rate was 12.2%. The age-adjusted standard mortality ratio (SMR) was calculated to compare the risk of death in patients with epilepsy to the general population. Patients with epilepsy had a 3.5-fold higher risk of death as compared with the general population (SMR: 3.47, 95% CI: 2.46-4.91). The Cox proportional hazards regression model was used to assess relevant clinical contributions to death. Patients with an age-at-onset > or = 40 years had a 4-fold higher risk of death as compared with those with an earlier onset. The multivariate analysis revealed that age-at-onset between 40 and 59 years, tumor etiology, and being male increased the risk of death in epilepsy. One-third of the deaths in patients with age-at-onset between 40-59 years died of liver cirrhosis and hepatoma. Hepatitis B virus infection is endemic in Taiwan, and this is closely associated with liver cirrhosis and hepatoma. Whether anticonvulsants contributed to the hepatotoxicity that led to fatal liver disease in this group needs further investigation.