Abstract: Objective: Hyperosmia may be an early manifestation of hypocortisolism and may be mistakenly diagnosed as osmophobia. However, sertraline therapy incidentally alleviated the phobic symptoms and hindered accurate diagnosis.Case report: A 41-year-old man was diagnosed as having osmophobia. Initial sertraline treatment relieved the symptoms, but its cessation resulted in recurrence of osmophobia. Endocrinological examinations revealed severe hypocortisolism and partial hypopituitarism with isolated adrenocorticotropic hormone deficiency. After prednisolone supplementation, his condition dramatically improved.Conclusion: We recommend that, before intervention with selective serotonin reuptake inhibitors is performed, the hypothalamic–pituitary–adrenal axis be evaluated in psychiatric patients presenting with co-occurring olfactory change.