The most threatening early complication and predictor of poor outcome after an aneurysmal subarachnoid hemorrhage (aSAH) is a rebleed. To evaluate what proportion of rebleeds might be prevented by early treatment, we assessed the time interval from the initial hemorrhage to rebleed, and the location of the patient at the time of rebleed. Patient characteristics, World Federation of Neurological Surgeons grade on admission and modified Rankin Scale outcome scores, referring hospitals and time intervals from initial hemorrhage to treatment of 293 patients treated between 2008 and 2011 were evaluated. Time intervals to rebleeds and location of the patients at the time of rebleed were retrieved. Rebleeds were confirmed by CT in 12% of patients, and an additional 4% of patients was diagnosed as having a possible rebleed. Sixty percent of rebleeds occurred after admission to the treatment center. Almost all rebleeds occurred within 24 h, with a median time interval between initial hemorrhage and rebleed of 180 min. A significantly shorter time to treatment and a higher mortality were seen in the group of patients with a rebleed. Approximately, one in six patients with an aSAH had a rebleed, of which a majority might have been preventable because they occurred after admission to the treatment center. A reduction in the rebleed rate seems feasible by securing the aneurysm as soon as possible by improving in-hospital logistics for early aneurysm treatment. Alternative options, such as immediate administration of antifibrinolytics, are being explored in a multicenter trial.