OBJECTIVE To investigate the relationship between BMI, WHR and billary tract cancers (CBT).METHODS A population-based case-control study was conducted in urban Shanghai from June 1, 1997 to May 31, 2001 involving interviews with 627 new cases of biliary tract cancers aged 35 to 74 years and 959frequency-matched population controls by gender and age in five-year groups. All subjects were interviewed in person by trained interviewers using a structured questionnaire. An unconditional logistic regression was performed to calculate adjusted odds ratios (Ors) and 95% confidence intervals (Cis).RESULTS Obesity was associated with an increased risk of gallbladder cancer across adulthood at ages 20-29 and 30-39 in females. Compared with subjects in the lowest quartile of WHR, Ors for the highest quartile and P for trend for cancers of gallbladder and extrahepatic bile duct both reached significant levels among males and females.CONCLUSION Our observations in urban Shanghai suggested that obesity in early adult life may contribute to the risk of gallbladder cancer, and increased WHR may substantially elevated risk of cancers of the gallbladder and extrahepatic bile duct.