Communication between patients with cerebral aneurysms and consulting neurosurgeons remains unstudied in Japan. The present clinical study surveyed patients with unruptured cerebral aneurysms and their neurosurgeons after explanation of the disease and its treatment options and expected outcomes in clinic visits using a one-page written questionnaire about treatment options and decisions given to patients and their neurosurgeons. The numbers of participating patients and neurosurgeons were 42 and 9, respectively, and 42 paired patient-neurosurgeon responses were obtained. Agreement was quite low (kappa = 0.17-0.31 for 6-point Likert scale and kappa = 0.44-0.67 for 2 category scale) regarding the "best" treatment for each patient as agreed on by the patient and neurosurgeon. Agreement in the understanding of treatment options and general application was unexpectedly low (kappa = 0.12 and 0.01 for 6-point Likert scale and kappa = not applicable and -0.03, respectively, for 2 category scale). Agreement tended to be higher between experienced neurosurgeons and patients than non-experienced neurosurgeons and patients. Patients estimated much higher risks of stroke or death after surgical intervention (p < 0.001) or no intervention (p = 0.006) compared with the estimates offered by their neurosurgeons.