Cervical lymphadenitis due to Mycobacterium avium complex is relatively common in children but is extremely rare in adults, except in immunocompromised patients. In this report, we describe a case of isolated cervical lymphadenitis in an immunocompetent adult woman. Histological examination of the excised lymph node showed multiple epithelioid cell granulomata with necrosis. Further, from the biopsy specimen cultures, we identified the causative organism as Mycobacterium avium. The patient was not administered any antimycobacterial agents because the affected lymph node was removed completely and because of uncertainty regarding the benefits of such treatment. No recurrence was observed in the patient's neck region during postoperative follow-up at 8 months.