Introduction: Leptospirosis is a spirochetal zoonosis affecting humans and animals. It is underreported and underdiagnosed in India, and is a major public health problem. In a retrospective study, the data collected from the suspected cases of leptospirosis for a period of 1 year from a tertiary care teaching hospital were analysed. Materials and Methods: A total of 642 serum samples from suspected leptospirosis patients were collected between January 2012 and December 2012. The clinical data including demographic parameters of 135 hospitalized patients tested positive by immunoglobulin M enzyme-linked immunosorbent assay (IgM ELISA) were analyzed. Results: Of the 642 patients who were admitted with suspicion of leptospirosis, 135 showed serological evidence of leptospirosis with an adult and male preponderance, and most cases were reported during a period of heavy rainfall. The most common clinical symptoms were fever, thrombocytopenia, elevated liver enzymes, acute renal failure, and acute respiratory failure. Mortality was due to multiorgan failure. Conclusion: Leptospirosis is more common during the monsoon. Common complications include renal failure and hepatic dysfunction. Death is due to multiorgan failure.