Recurrent low-grade gliomas in children were studied with special reference to correlation between the computed tomography (CT) scan and pathological findings at recurrence. During the past 16 years (1970-1986) 105 cases of primary pediatric brain tumors were treated in our hospital. Seventeen of these had low-grade glioma, seven of which (five astrocytomas, one ependymoma, and one subependymoma) had recurrence of tumor by the end of 1987. The enhanced CT findings were classified into three types--cystic, false cystic, and solid, according to Lapras' classification. The pathological findings of recurrent tumors were reviewed with particular attention to malignant transformation. The results showed that in two out of three cases where CT findings had changed from initial cystic to solid type at recurrence malignant transformation was revealed. Enhanced CT scan was also useful for detecting small asymptomatic recurrent tumors in children. On the other hand, surgical procedures and adjuvant therapies demonstrated no significant relationship with recurrence. It is suggested that the recurrence of low-grade glioma in children is not rare, and that changes in findings on contrast enhanced CT might reflect malignant transformation in a recurrent tumor, necessitating a careful follow-up.