Background Second victims, defined as health care team members being traumatized by an unanticipated clinical event or outcome, are supposed to be a common phenomenon in health care. Surveys in the US health care system indicate high incidence rates among physicians between 10 and 44%. However, no systematic assessment of second victims in health care in German speaking countries has been published yet and no validated German questionnaire for assessing incidence of and impact on second victims exists. Therefore, we initiated the SeViD (Second Victims im Deutschsprachigen Raum/second victims in German speaking countries) project and developed a German questionnaire for the assessment of second victim incidents. Methods Based on an intensive literature review of available questionnaires in English we defined a preliminary version of our questionnaire consisting of 4 domains and 14 items. This version was subject to cognitive pretesting using paraphrasing, probing and think aloud methods in order to ensure content validity. Retest reliability of second victim symptoms was assessed three weeks after the initial pretest. Results Fifteen health care professionals (physicians, nurses, therapeutic and diagnostic professions and administrative staff) of hospitals in Germany (n=6) and Austria (n=9) with or without previous second victim experience participated as volunteers for all pretests after informed consent. Seven items in three domains were slightly modified based on cognitive pretests. Retest reliability for second victim symptoms was rho = 0.76. Mean duration of completion for this questionnaire took 9:01 (±3:05) minutes in case of a previous second victim experience and otherwise 4:19 (±0:59) minutes and was regarded acceptable by all volunteers. No volunteer regarded any question to be inappropriate. Conclusion We successfully developed a validated questionnaire assessing the impact of the second victim phenomenon in inpatient health care facilities. This questionnaire will be used in different settings for health care professionals and for stand-alone baseline assessment as well as pre/post-survey along with complex educational interventions to reduce negative impacts of the second victim phenomenon.