We investigated the association of Dupuytren's contracture with smoking and with alcohol by a case-control study in which 222 patients having an operation for this condition were matched for age, operation date and gender with control patients having other orthopaedic operations. Fifty of the cases were also each matched with four community controls. Data were collected by postal questionnaire. Dupuytren's contracture needing operation was strongly associated with current cigarette smoking (adjusted odds ratio 2.8 (95% confidence interval (CI) 1.5 to 5.2)). The mean lifetime cigarette consumption was 16.7 pack-years for the cases compared with 12.0 pack-years for the controls (p = 0.016). Dupuytren's contracture was also associated with an Alcohol Use Disorders Test score greater than 7 (adjusted odds ratio 1.9 (95% CI 1.02 to 3.57)). Mean weekly alcohol consumption was 7.3 units for cases and 5.4 units for controls (p = 0.016). The excess risk associated with alcohol did not appear to be due to a confounding effect of smoking, or vice versa. Smoking increases the risk of developing Dupuytren's contracture and may contribute to its prevalence in alcoholics, who tend to smoke heavily.