Objective: This study aimed to evaluate the development of adjustment disorder according to the ADNM-20 (Adjustment Disorder New Module-20) scale in participants who were followed up for Covid-19 infection. Methods: A cross-sectional survey was conducted from September to November 2020. After sample size calculation, we aimed to reach minimum 170 people out of 1290 people who applied to the hospital for Covid-19 disease treatment. Participants were selected from the patients admitted to the hospital using a simple stratified random sampling method. We reached 182 people after treating the patients who were followed up with Covid-19 infection in a University Hospital in Istanbul, Turkey. A questionnaire and the Adjustment Disorder New Module-20 scale were applied via phone / mail at the end of the 6th month after Covid-19 related hospital admission by researchers. Results: Adjustment disorder was found in 28.8 % (n=42) of the participants disorder according to the ADNM-20 scale. While the rate of development of adjustment disorder due to Covid-19-related stress was 26.7 % (n=39); the rate of development of adjustment disorder due to non-Covid-19 stress was found to be 2.1 % (n=3). With the increase in stress load, the development of adjustment disorder increased significantly. The frequency of developing Covid-19-related stress-related adjustment disorder was statistically significantly increased with the duration of exposure to stress. Conclusion: We have found out that one out of every four people who apply to the hospital for healthcare services due to Covid-19 infection may develop an adjustment disorder. Assessment of the adjustment disorder more frequently and making early interventions may contribute to the prevention of progressive mental disorders.