India is an endemic zone for hepatitis E virus (HEV), which is associated with both epidemic and sporadic infections. In West Bengal, only two hepatitis E outbreaks have been studied to date. However, sporadic cases of HEV infection also occur during inter-epidemic periods. The aim of this hospital-based study was to detect the prevalence of HEV infection in patients with acute sporadic hepatitis in West Bengal, India. Blood samples and clinical information were collected from 285 patients of both sexes and different ages with acute viral hepatitis (AVH) at Calcutta Medical College, Kolkata, a tertiary-care centre. Samples were tested for hepatitis B virus (HBV) surface antigen, anti-hepatitis C virus antibodies, anti-hepatitis A virus IgM and anti-HEV antibodies (IgM and IgG) by ELISA. Only those patients with AVH who were in their first week of illness and negative for all hepatotropic viral antibodies were tested for HEV RNA by reverse transcriptase nested PCR. HEV was identified as the most common cause of AVH (41.8 % of patients), followed by HBV (21.4 %), hepatitis A virus (17.2 %) and hepatitis C virus (4.6 %). Co-infections with more than one virus were found in 22 patients, with HBV–HEV the most common co-infection (3.8 %). Only 14.7 % of patients had no viral marker. To the best of our knowledge, this is the first documented epidemiological study of acute sporadic hepatitis with HEV in the state of West Bengal, India, indicating that this state is an endemic zone for HEV infection.