RATIONALE: Respiratory epithelial adenomatoid hamartomas (REAH) are benign tumors. The clinical presentation of REAH often resembles that of nasal polyps or inverted papillomas. Owing to the lack of specific clinical symptoms or imaging findings, the diagnosis is usually confirmed only by pathological examination after surgery and misdiagnosis is common. Therefore, we report this case of nasal REAH that was misdiagnosed as a nasal polyp. Clinical cases of nasal polyps with hamartoma are very rare. Pathological biopsy, complete removal of the lesion by surgery and postoperative follow-up are essential for the diagnosis and treatment of REAH. PATIENT CONCERNS: The patient had been experiencing bilateral anosmia for 6 years without any obvious triggers. He also experienced nasal congestion and mucopurulent nasal discharge after exposure to cold and alcohol. DIAGNOSIS: Analyzing the pathological findings that the patient was diagnosed with right-sided respiratory epithelial adenomatoid pleomorphic histiocytoma and left-sided nasal polyps. INTERVENTIONS: Nasal endoscopic surgery was performed to remove bilateral nasal lesions and send them for routine pathological examination. OUTCOMES: After surgery, the patient's sense of smell was slightly restored to normal. LESSONS: Our case report findings suggest that clinical attention should be paid to the possibility of nasal REAH with nasal polyps in bilateral nasal polypoid masses, particularly if the olfactory fissure is involved.