The clinical course of subdural fluid collection(SDGC) was studied in 32 cases of patients which underwent craniotomy for intracranial aneurysm and analysed regard to patients' age, sex, degree of initial subarachnid hemorrhage, the operating time of aneurysm, duration to appearance of SDFC from craniotomy, changes of clinical state, disappearance time, site, maximal thickness and changes of SDFC, management and prognosis. The results were summarized as followings. 1) SDFC was found in 33 of 85 patients(38.8%). 2) The older age group had higher incidence of SDFC than the younger age group. 3) The older age grop had thicker SDFC than the younger age group in the maximal thickness of SDFC, and that was statistically significant. 4) The early surgery group of aneurysm had lower incidence of SDFC compared with the delayed surgery group. 5) There were minimal changes of clinical states when SDFC was diagnosed by brain CT. 6) The frontal area was involved in all cases and bilateral involvement was noted in 15 cases(45.5%). 7) Surgical procedures were needed in 8 cases(24.2%) of SDFC, including 2 cases of chronic subdural hematoma. 8) Ventricular dilatation with spontaneous improvement of SDFC were noted in 8 cases(24.2%) and lumboperitoneal shunt for hydrocephalus was needed in only 2 cases of them.