The role of early radiotherapy in the treatment of low-grade gliomas is controversial. For this reason the impact of radiotherapy on quality of life was studied in long-term survivors of biopsy-proved low-grade gliomas without signs of tumor recurrence. Twenty patients (age range, 18–66 years) had been treated with early radiotherapy; the other 21 patients (age range, 19–65 years) had undergone surgery or biopsy only. The interval from diagnosis to testing ranged from 1 to 12 years (mean, 3.5 years). Nineteen patients with low-grade hematological malignancies, surviving 1 to 15 years without central nervous system involvement, served as control subjects. Apart from the neurological and functional status, the patients' cognitive, affective, and psychological status was determined. None of the survivors had significant neurological impairment and the Karnofsky index for them was at least 70. However, more specific examinations of cognitive functions and the affective status (Profile of Mood States) indicated that, compared to the control subjects, the patients with low-grade gliomas had significantly more cognitive disturbances and suffered more frequently from fatigue and depressed moods. The two groups with low-grade gliomas, on the other hand, did not differ significantly on any of these measures. It is concluded that radiotherapy did not cause these disturbances and had no negative impact on quality of life in these patients.