The epidemiology of notified cases of campylobacter gastroenteritis in adults in Nottingham Health District was investigated using a case-control study with a postal questionnaire to ascertain data on risk factors. Over a 14-month period 531 cases (a 73% response rate of all laboratory confirmed cases) and 512 controls replied. Conditional logistic regression analysis was used to determine independent associations with infection. These included foreign travel (odds ratio (OR) 3.4; 95% confidence intervals (CI) 2.0-5.7), diabetes mellitus (OR 4.1, CI 1.1-17), medication with omeprazole (OR 3.5, CI 1.1-12) and H2 and H2 antagonists (OR 3.7, CI 1.3-15), contact with puppies (OR 11.3, CI 1.2-105), eating chicken (OR 1.4, CI 1.1-1.8) and drinking milk from bottles with tops damaged by a bird (OR 3.3, CI 1.0-11). Preparing main meals (OR 0.9, CI 0.8-1.0) and drinking delivered milk (OR 0.6, CI 0.4-0.9) were associated with a reduced risk of campylobacter infection. Foreign travel was reported in 25% of cases and another 15% had significant associations with other risk factors. The majority of cases, 60%, remained unexplained, indicating the need for further evolution of sporadic cases.