We report a case of subacute psychotic symptoms in a patient with germ cell tumor (GCT). The 32-year-old malepatient showed progressive psychotic symptoms with diagnosis of GCT. His psychotic symptoms included delusions of reference and persecution. Brainmagnetic resonance imaging, electroencephalography, and laboratory examinations were performed to evaluate any other causes. The clinical, neuroimaging, and laboratoryreview in this case suggested that the progressively developed psychotic symptoms that led to chronic deterioration were caused by the GCT. This is the case report in which subacute atypical psychotic symptoms in his thirties could develop from a GCT based on previous basic research findings showing the correlations of psychotic symptoms with GCT although it has the limitation of so early speculation.