Non-saccular aneurysms (NSAs) of the internal carotid artery trunk include blood blister-like aneurysms (BBAs) and dissecting aneurysms (DAs), which are susceptible to disastrous intra- and postoperative bleeding. This study was conducted to clarify the clinical features of NSAs and the results of early bypass and trapping. Nineteen ruptured NSAs were identified in 937 patients with subarachnoid hemorrhage (SAH). The principal treatment was to trap the aneurysm following bypass surgery as soon as possible after SAH onset. Angiography revealed nine BBAs and ten DAs. Eight patients (four BBA and four DA) were treated in the chronic stage because of delayed arrival (n=3) or lack of aneurysm on initial angiography (n=3), or other reasons (n=2). The remaining 11 patients underwent early surgery using trapping after bypass, except for one BBA-type (clipped). During surgery, corresponding intraoperative findings were confirmed for each aneurysm type. There were six preoperative reruptures; five were determinant of patient outcome. In 14 patients without preoperative rerupture influencing outcome, 11 patients were independent at discharge and three patients dependent due to surgical complication. There was one case of minor intraoperative bleeding; no postoperative rerupture occurred. There was no delayed vasospasm-related deficit, although temporary symptomatic spasm occurred in three patients. Early bypass and trapping appeared to be an acceptable treatment strategy for these NSAs eliminating intra- and postoperative bleeding and not increasing a chance of delayed vasospasm.