In these days when the effect of theCOVID-19 pandemic is felt with all its severity, the findings of re-infection in people who have had COVID-19 disease have led to some questions about the natural immunity against this disease. Here, we report a possible COVID-19 reinfection. The second episode confirmed by RT-PCR with a more severe clinical picture one month after an incidentally detected first episode with mild symptoms of a doctor working as a microbiologist at a training research hospital. While a 47-year-old female doctor was working in a tertiary hospital serving as a reference hospital for the diagnosis and treatment of COVID-19 patients, symptoms of sore throat, cough and runny nose appeared on October 25. The patient, with a history of chronic tendinitis, COPD, asthma and allergic rhinitis, attributed these symptoms to her previous clinical diagnosis and did not consider consulting a doctor or testing for COVID-19 due to the mild course of symptoms. SARS-CoV-2 Ig G antibodies were found to be positive in a screening study conducted on November 11 in the patient whose complaints resolved within a few days. RT-PCR performed thereafter was reported as negative. The RT-PCR test performed on December 2 of the patient who complained of fever and severe weakness, immediately after her colleague had COVID-19, was interpreted as positive. No signs of viral pneumonia were found in the thoracic CT when the cough complaint of the patient who received COVID-19 treatment did not improve. The patient's complaints regressed with the addition of phenocodine to her treatment, and the RT-PCR test on December 12 was reported as negative. Further analysis of the frequency and possible causes of COVID-19 reinfections will be needed in the near future.