Short-term pretreatment of patients with subarachnoid hemorrhage, but without hematomas causing mass effect, who presented in poor neurological condition at admission was evaluated as a protocol for the selection of candidates for radical surgery. One hundred-three patients were pretreated for 12 hours with control of blood pressure and intracranial pressure, using diuretic agents and/or ventricular drainage. Neurological improvement was observed for 32 of 47 patients in Grade IV at admission and 23 of 56 patients in Grade V (P < 0.01). Hydrocephalus requiring drainage was more common (P < 0.05) and the interval between onset and admission was shorter (P < 0.01) for the improved group. Clipping surgery was performed for all patients in Grade III or better and for patients in Grade IV who were less than 75 years of age and without systemic complications, i.e., 38 of 47 patients in Grade IV and 16 of 56 patients in Grade V at admission. Good outcomes (defined as moderately disabled or better on the Glasgow Outcome Scale) were achieved by 34 of 38 patients in Grade IV and 10 of 16 patients in Grade V (P < 0.01). The proportion of patients in Grade IV after pretreatment was lower for Grade IV (2 of 38 patients) than for Grade V (9 of 16 patients) (P < 0.00001). However, none of the 49 patients who underwent nonsurgical treatment achieved good outcomes. Our protocol may be beneficial for the selection of candidates for radical surgery among patients with subarachnoid hemorrhage but without hematomas who are in poor neurological condition at admission and for the improvement of postoperative outcomes.