Background In the United States, lawsuits against physicians have had an impact on their behaviour, resulting in overdiagnosis and other forms of 'defensive medicine'. Does a similar situation exist in Switzerland? Using prostate-specific antigen (PSA) screening as an example, we surveyed Swiss physicians and assessed the extent to which liability fears influenced their recommendation for testing. Methods At a continuing medical education conference we distributed a pilot-tested questionnaire to 552 participants. Two hundred and fifty of them (45%) completed the questionnaire. Results Of the participants, 158 (68%) were general practitioners and 73 (32%) specialists in internal medicine. Seventy-five per cent of both groups recommend regular PSA screening to men older than age 50. Yet only 56% of the general physicians and 53% of the internists believe that PSA measurement is an effective screening method. A substantial proportion of the physicians -41% of general practitioners and 43% of internists -reported that they sometimes or often recommend this test for legal reasons. Conclusions Defensive medicine is not a phenomenon particular to the USA, but is also observable in Switzerland. This result is surprising, given that in Switzerland and other European countries, a physician who does not recommend a test or treatment whose effectiveness is controversial need not fear litigation.