Background and Objective: The COVID-19 pandemic has threatened global health and increased the possibility of anxiety symptoms. The present study aims to investigate the frequency of post-traumatic stress disorder (PTSD) symptoms after the outbreak of COVID-19 in patients referred to the Mazandaran Welfare Organization in Mazandaran Province, Iran, in 2020. Materials & Methods: In this descriptive-analytical study, 255 people enrolled. All participants were evaluated based on calls or in-person visits to the Mazandaran Welfare Counseling Center in Mazandaran Province, Iran, using the post-traumatic stress disorder checklist (PCL-5) with a cut-off point of 33 to diagnose PTSD. Also, the quality of sleep was measured based on the Pittsburg questionnaire. The P<0.05 was considered significant. Results: The prevalence of PTSD in the high-risk population of welfare referees was 40.4% (CI 95%: 34.4 -46.4). The prevalence of PTSD had a significant relationship with the level of education (P=0.03). There was a positive and significant correlation of 30.2% between sleep quality scores and PCL-5 scores (P< 0.001). Conclusion: Considering the high prevalence of PTSD in people who are referred to welfare centers, as well as the availability of most of these individuals, it is possible to reduce the damage to this group by identifying factors related to PTSD and health planning.