Background: The increased morbidity and mortality associated with nosocomial infections in the intensive care unit (ICU) is a matter of serious concern today. Aims: To determine the incidence of nosocomial infections acquired in the ICU, their risk factors, the causative pathogens and the outcome in a tertiary care teaching hospital. Materials and Methods: This was a prospective observational study conducted in a 12 bedded combined medical and surgical ICU of a medical college hospital. The study group comprised 242 patients admitted for more than 48 h in the ICU. Data were collected regarding severity of the illness, primary reason for ICU admission, presence of risk factors, presence of infection, infecting agent, length of ICU and hospital stay, and survival status and logistic regression analysis was done. Results: The nosocomial infection rate was 11.98% (95% confidence interval 7.89-16.07%). Pneumonia was the most frequently detected infection (62.07%), followed by urinary tract infections and central venous catheter associated bloodstream infections. Prior antimicrobial therapy, urinary catheterization and length of ICU stay were found to be statistically significant risk factors associated with nosocomial infection. Nosocomial infection resulted in a statistically significant increase in length of ICU and hospital stay, but not in mortality. Conclusion: Nosocomial infections increase morbidity of hospitalized patients. These findings can be utilized for planning nosocomial infection surveillance program in our setting.