This study analyzes the utility of peroperative cortical language mapping applied to the surgery of high-grade gliomas situated within or in close vicinity to speech areas. Fifteen consecutive patients harboring high-grade gliomas located in the dominant hemisphere, causing regressive or minor language troubles, underwent awake craniotomy in our institution between June 1998 and April 2000. The technique of cortical stimulation under local anesthesia for language mapping, initially described by Ojemann and colleagues, was applied with some modifications. All patients tolerated awake craniotomy except one, who was intubated after the mapping procedure. Mapping results confirmed a high variability in location of language sites. It was possible to achieve a gross total tumor removal in all cases. Nine patients (60%) exhibited a transient postoperative aggravation. Two patients (13%) presented permanent phasic aggravation. One patient died 16 days after surgery from pulmonary embolism. Five patients died for tumor progression, with a mean survival time of 16.4 months and a median high-quality survival period of 14.2 months. With a mean follow-up of 9.9 months (range, 18-6 months), the 9 survivors are recurrence-free and reveal no significant change in linguistic abilities. This technique is well tolerated and consents to maximize the extent of surgical removal while minimizing the risks of permanent postoperative deficits. This results in an improvement of survival and quality of life.