Knowledge about hepatitis B and C was assessed in a cross-sectional study of 300 adults aged 18 or older attending family medicine clinics at The Aga Khan University Hospital, Karachi. Most knew that hepatitis B and C are viral diseases that primarily affect the liver, but knowledge about risk factors for disease transmission was poor. Approximately 70% knew that hepatitis B is vaccine preventable; 60% had the misconception that hepatitis C is also vaccine preventable. The majority incorrectly believed that people with hepatitis B or C should follow the diet 'parhaiz'. Generally women knew more than men about the diseases. This study suggests that health education about these infections should be provided to the public. Family physicians can play an important role in educating people about the prevention of these diseases.