Introduction: Healthcare personnel face a wide range of challenges during the COVID-19 pandemic, such as increased workload, fears of disease transmission for themselves and their families, working with new and frequently changing protocols and personal protective equipment. This study aimed to evaluate the anxiety levels and sleep quality of health care workers who carried out filiation studies due to the COVID-19 pandemic in Sakarya and the factors that may be associated with them. Method: This cross-sectional study planned to reach all of the healthcare workers who took an active role in filiation within the scope of the COVID-19 pandemic between 1-31 July 2020 in Sakarya. Data were collected voluntarily with online questionnaires. The participants' sociodemographic characteristics, anxiety status, and sleep quality were evaluated with a questionnaire consisting of three parts. Beck Anxiety Inventory (BAI) was used to assess the participants' anxiety levels, and the Pittsburgh Sleep Quality Index (PUKI) was used to evaluate their sleep quality. Results: 137 (88.9%) of 154 healthcare workers who took an active role in filiation were reached. Of the 137 health workers participating in the study, 83.9% were female, and 16.1% were male. The mean age of the participants was 35.7±7.3 years, and the median was 34 (29 in the 1st quarter, 42 in the 3rd quarter). When evaluated according to their profession, 38.0% were midwives, 17.5% were nurses, and 14.6% were doctors. The mean BAI score of the participants was 15.19±13.07, and the mean PUKI score was 7.92±3.60. When BAI scores are evaluated; The BAI score was significantly higher than the other groups in women, divorced/widowed, chronic diseases, and those who had previously worked in the filiation study of another infectious disease. In women, those with chronic conditions, and those previously involved in the filiation study of another contagious disease, the PUKI score was significantly higher than the other groups. There was a weak positive correlation between the mean daily filiation time and the BAI score (r=0.213 p=0.013). A moderate positive correlation was found between the BAI and PUKI scores (r=0.625 p<0.001). Conclusion: It was determined that the mental health of some healthcare workers in the filiation team was affected due to the COVID-19 pandemic in Sakarya. It is thought that interventions to protect and improve healthcare workers' mental health who work in extraordinary situations such as pandemics are necessary.