Defensive medicine takes place when healthcare personnel modify their behaviour with the aim of reducing their exposure to legal challenges from patients. The phenomenon is directly related to the significant growth in medical malpractice litigation over recent years. This article presents the results of two research surveys aimed at measuring the extent of defensive behaviours on the part of doctors in Italy and at understanding the reasons for them. The first study (the National Study (NS) was conducted in respect of a nation-wide sample of general practitioners, while the second (the Local Study (LS) was conducted in respect of two groups of specialists (surgeons and anaesthetists) in a regional hospital. 77.9% of the general practitioners interviewed for the NS (responses were received from 37% of the 1000 GPs to whom the questionnaire was sent) declared that they had practiced at least one form of defensive medicine during the previous working month. The figure for the LS was 83.3%. This article discusses the factors, such as the blame culture and the increase in medical malpractice litigation, that may lead to defensive behaviours and result in negative effects both in terms of costs and patient safety. A clear need emerges for a different approach to the problem of medical error - at a cultural, organizational and legal level - just as in the case of other organizations subject to high risk. The deterrent of punishment does not increase the reliability of such organizations, nor does it improve the level of safety in them.