The first objective in this study was to identify the errors of incidents and accidents that occurred in general and mobile X-ray examinations. Based on the analysis of results, the second purpose in this study was to propose useful measures to prevent such errors. As much as 553 radiological technologists in the Gunma Prefecture were surveyed on their experience with errors related to general and mobile X-ray examinations. The questionnaire asked for descriptions of errors experienced during examinations and the responses given (multiple answers possible), and evaluations of the degree of busyness on a five-point scale. A total of 115 questionnaires were returned. Analysis revealed that there was no significant relationship between errors and degree of busyness for either general or mobile examinations. The most frequent error both in general and in mobile examinations was to X-ray a patient mistakenly, the cause of which was cited as failure to confirm the patient's name. After the use of solution priority number to evaluate proposed preventive measures, such as finger-pointing and call, independent double-checks, and verbal self-confirmation would be the simplest and most easily implemented countermeasure.