BACKGROUND The aim of the present study was to evaluate the technical viability of the unilateral pterional approach to simultaneously treat symmetrical bilateral aneurysm (mirror image) of the middle cerebral arteries (SBAMCA) and to determine the morbidity and mortality rates of this approach. METHODS Forty-six patients with SBAMCA underwent unilateral pterional craniotomy within a period of 9 years. Most patients were women (24, 80.0%) and mean age was 40.7 years. RESULTS Obliteration of the contralateral aneurysm was not possible in 16 patients (34.8%) because of brain edema in 8 patients operated on during the acute phase, lateral projection of the aneurysm in 3, a very long contralateral M1 segment in 4, and the presence of atheromatous plaques at the MCA bifurcation and aneurysm neck in 1. The remaining 30 patients (65.2%) were submitted to the proposed treatment. Final evaluation showed that 26 patients (86.7%) were Glasgow Outcome Scale (GOS) V, 1 patient (3.3%) was GOS IV, 2 patients (6.6%) were GOS III, and 1 patient (3.3%) was GOS I. CONCLUSIONS The unilateral pterional surgical approach to treat SBAMCA is a technically viable procedure associated with low morbidity and mortality. However, it requires a neurosurgeon experienced in cerebral aneurysm surgery and the appropriate technical conditions.