Aim: In the progression of the diseases, the psychological and stress levels of the patients affect the course of the disease. This situation is also important and should be analyzed in the follow-up of COVID-19 patients. In this study, it was aimed to investigate the stress levels of COVID-19 patients in our hospital isolation services.Materials and Methods: A prospective cross-sectional study is conducted in our isolation services where possible/definite COVID-19 patients older than 18 years old are followed. According to the patients' swap test results, patients are divided into two groups; group 1: COVID-19 possible, and the group 2: COVID-19 definitive groups. The demographic properties of the patients investigated, and the "Perceived Stress Scale", was applied to all groups the day after the swap test results were completed, and the outputs were analyzed.Results: A total of 157 patients with voluntary participation (94 possible and 63 definite COVID-19 patients) were included. The mean age of the patients was 39.34 ±12.87 years and 54.1% were women. In the analysis of the stress levels of the patients, while both groups have increased scores, but the Perceived Stress Scale (PSS) score was higher in COVID-19 definite group and statistically significant (p<0.001). The patients with high stress levels (PSS score ≥36) were found to be 7.4% (n=7) in group 1; 77.8% (n=49) in group 2; and 35.7% (n=56) in total, and statistically significant (p<0.001). When we investigate the source of the information about COVID-19 of the patients, television was the leading (91.7%) source. The most frequent preventive measure was hand washing in both groups and were not statistically significant (p>0.05).Conclusion: Stress levels of patients increase in COVID-19 pandemic. It should be kept in mind that the stress levels may be higher particularly in positive cases, and psychiatric support and preventive measures should be occupied accordingly.