Aim. The most widely reported problems among people who have been hospitalized for COVID-19 are those associated with mental health. The aim of the study was to determine the incidence of PTSD in patients hospitalized due to COVID-19 and to determine predictors of the risk of its occurrence. Material and methods. The study group included 250 people after hospitalization due to COVID-19. Several standardized measurement tools were used: the PCL-5, PSS-10, ERRI, SPP-15, and PANAS. Results. Overall, 55.6% of respondents qualified for a diagnosis of PTSD. These were mostly people hospitalized for more than two weeks, with a more severe course of the disease, examined within three and six months after hospitalization. The regression model includes factors related to the course of treatment and psychological variables: some increase the risk of PTSD (i.e., perceived stress, intrusive ruminations and negative emotions), while others are protective factors (i.e., resilience, deliberate ruminations and positive emotions). Overall, the regression model explains 72% of the total variance. Intrusive ruminations, explaining 59% of the variance, and perceived stress (12%) appeared the most significant for predicting PTSD. Conclusions. As patients diagnosed with PTSD require therapeutic assistance, it is essential to identify both risk and protective factors as these may be helpful in improving the therapy process and facilitating preventive activities.