Despite the most effective treatment currently available, the majority of supratentorial gliomas in adults will recur. At the time of recurrence, most of these tumors will have acquired malignant characteristics. Available treatment options, at recurrence, include reoperation, radiotherapy, chemotherapy, and immunotherapy, alone, or in combination. Phase II trials report reasonable response rates and acceptable morbidity with these modalities, but cure remains difficult to achieve. The influence of selection bias and the lack of standardization between trials confounds the comparison of relative treatment efficacy. The choice of therapy at recurrence is often dictated by the toxicity of previous treatments, tumor growth patterns, and the patient's functional status. The proper management of low-grade lesions that recur without evidence of malignant progression is even more problematic, and less well studied. Based on a thorough search of the current literature, this review article presents a critical analysis of these different therapies, along with the background information required to make these assessments, i.e., the definitions of recurrence and treatment response, the use and interpretation of imaging studies, the various schemes employed for histopathological grading, the natural history of the different gliomas after recurrence, prognostic factors, patterns of tumor growth, the effects of prior therapy, and tumor biology. Promising new treatments are discussed as well.