OBJECTIVES/HYPOTHESIS: To investigate causative viruses in patients with postviral olfactory disorders (PVOD). STUDY DESIGN: Case-control study. METHODS: One hundred fifty-one consecutive patients diagnosed with PVOD were enrolled, and samples from 38 patients who visited the doctor within 3 months of symptom onset were collected and analyzed. Thirty-two individuals who underwent surgery for nasal septal deviation during the same time period were collected as the control group. The Sniffin' Sticks psychophysical olfactory test was used to evaluate olfactory function. Olfactory cleft specimens were collected using nasopharyngeal flocked swabs (COPAN FLOQSwabs). Eighteen viruses were tested for with the Luminex xTAG RVP FAST v2 Assay Kit. RESULTS: Out of the 38 patients with PVOD, rhinoviruses were detected in 13 patients, and coronavirus OC43 was detected in one patient. The frequency of positive virus detection in the patients with anosmia was higher than in those with hyposmia (58.8% vs. 19.0%, P = 0.018). In control group, rhinovirus was identified in one patient (3.1%). Nasal obstruction was the most common symptom and was experienced by 71.0% of patients. CONCLUSIONS: Rhinovirus and coronavirus are more commonly identified in PVOD. Our methods represent an approach to screen for viruses that may be involved in PVOD. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:158-164, 2021.