We conducted an international web-based survey to obtain information about the informed consent (IC) procedures used in genetic epidemiological studies of multifactorial diseases. In total, 53 responses from 15 countries were obtained. We found that support personnel such as research coordinators took charge of a large part of the IC procedures, especially in the United States. Although most support personnel had documented and/or verbal confidentiality agreements, and all had undertaken IC training, accreditation examinations were only conducted in 60% of studies. Peripheral blood specimens were reported to be a major source for DNA extraction, whereas noninvasive methods were used in some studies. To undertake high-quality genetic epidemiological studies, participation of a large number of volunteers is essential for independent sets of samples that allow confirmation of results. On the basis of the survey results obtained, support personnel dedicated to completing the IC procedures are reported to be beneficial and indispensable in alleviating the burden on medical doctors, helping participants to make autonomous decisions and promoting genome research. The establishment of a training program and accreditation system for such personnel is warranted, especially in Japan, where medical staff usually finds it difficult to conduct IC procedures in clinical settings due to heavy workloads.