Objective To report a case of a woman who presented with amenorrhea and masculinization secondary to an androgen-secreting granulosa cell (GC) tumor, with refractory masculinization. Design Case report. Setting University medical center. Patient(s) A 45-year-old woman with abrupt onset of virilization with high serum androgen levels. Intervention(s) Exploratory laparotomy with full staging. Main Outcome Measure(s) Surgical findings and histopathologic observations are included in this report. Result(s) Pathologic examination revealed an inhibin stain positive GC tumor of the adult type. Virilization has persisted for 8 years after surgery. Conclusion(s) Adult-type GC tumor is an extremely rare cause of virilization. Masculinization features may persist in the absence of high androgen levels.