Four rare cases of aneurysm of the lenticulostriate artery (LSA) are presented. LSA aneurysms were located at the origin in three patients and distally in one. Two cases were of multiple aneurysms, one was associated with hypertensive intracerebral hematoma (putaminal hemorrhage), and the other with moyamoya disease. Two patients were successfully treated by microsurgical procedures. The occurrence of LSA aneurysm suggests that aneurysm formation and growth are accentuated by hemodynamic alteration and stress.