BACKGROUND: Although there are a limited number of studies investigating the changes in olfactory bulb volume (OBV) and olfactory sulcus depth (OSD) values in the acute and subacute periods after COVID-19 infection, there are no studies conducted in the chronic period. PURPOSE: The aim of this study is to reveal the changes in OBV and OSD after COVID-19 in the chronic period. MATERIAL AND METHODS: A total of 83 people were included in our study, including 42 normal healthy individuals (control group) and 41 patients with COVID-19 infection (10-12 months after infection). RESULTS: The COVID-19 group included 41 patients with the mean age 40.27 +/- 14.5 years and the control group included 42 individuals with the mean age 40.27 +/- 14.4. The mean OBV was 67.97 +/- 14.27 mm(3) in the COVID-19 group and 94.21 +/- 7.56 mm(3) in the control group. The mean OSD was 7.98 +/- 0.37 mm in the COVID-19 group and 8.82 +/- 0.74 mm in the control group. Left, right, and mean OBVs and OSD were significantly lower in patients with COVID- 19 than the control individuals (all p < .05). CONCLUSION: Our findings show that COVID-19 infection causes a significant decrease in the OBV and OSD measurements in the chronic period.