Objectives: The study aimed to establish the current incidence and severity of spatial disorientation (SD) in Polish military pilots when flying different aircraft types over their entire careers, and to determine how SD training and pilots’ flight experience might benefit their recognition of situations that may cause SD. Material and Methods: Overall, 176 military Polish pilots (aged 33.8±7.72 years, the number of flying hours: 1194±941) flying different aircraft types, who attended the aviation medicine course, were surveyed and asked to report their episodes of SD. To collect anonymous data, a postal SD questionnaire (INFO PUB 61/117/5) was used. Results: In the overall incidence rate of SD (96%), the most commonly experienced SD illusion was “loss of horizon due to atmospheric conditions” (81%). More SD incidents were reported by pilots who had received SD training. Some differences in the categories of the most commonly experienced SD illusion episodes between aircraft types were found. A severe episode adversely affecting flight safety was categorized by 10% of the respondents. Conclusions: In Polish military aviation, episodes of SD are a significant threat to aviation safety. There is evidence for the beneficial effects of SD training in the improvement of pilots’ ability to recognize those factors that lead to SD. Int J Occup Med Environ Health. 2020;33(6):791–810