We have conducted a study to ascertain the pattern and background of lawsuits related to the practice of radiotherapy among physician-members of the Gilbert H. Fletcher Society. Eighty-four percent of the members of the society replied to the questionnaire; one-third have sustained a lawsuit with an actuarial probability of 30% at 10 years, 50% at 20 years, and 65% at 30 years. Lawsuits occurred across the spectrum of practice type, location, experience, disease site, and technique. Two-thirds of the suits were dropped or successfully defended. Regardless of the outcome, the experience of being sued was found to have influenced 33% of those sued to practice more conservatively. Recommendations of the membership directed towards minimizing the risk of being sued, while maintaining an aggressive treatment philosophy, are presented. Based on this study, we believe that formal medicolegal education should be included in the curriculum of radiotherapy residents' training program.