Objective: The quarantine process implemented to prevent the spread of infection during the coronavirus disease(COVID)-19 pandemic may negatively affect individuals. We aimed to evaluate the anxiety and loneliness levels of the quar antined individuals and determine the related factors. Materials and Methods: Two hundred ninety individuals who were brought to Turkey from abroad in May 2020, quaran tined in Sakarya province, participated in our descriptive cross-sectional study. The loneliness and anxiety levels, along withthe effects of the quarantine process, were evaluated. The sociodemographic information form prepared, Loneliness Scale(UCLA), State Anxiety Scale (STAI-1), and Trait Anxiety Scale (STAI-2), were used to collect data. Results: The mean age of the participants was 35.32±9.86 years and 79.7% were male. Participants who stated thatthey had a mental illness before the pandemic and those who reported that they needed a mental health professionalduring the pandemic scored significantly higher in the UCLA, STAI-1, and STAI-2 scales compared to others. TheUCLA and STAI-2 scores of participants with a high concern about contracting COVID-19 were higher than those withmoderate and low levels of anxiety. The quarantine process did not significantly affect the UCLA, STAI-1, and STAI-2scales of participants. Conclusion: Although quarantine was not found to affect anxiety and loneliness levels, it was observed that the basis ofanxiety in highly anxious individuals was constituted by worry about themselves or loved ones contracting the disease andeconomic effects of the process.