Lonidamine (LND) is a drug that interferes with energy metabolism of cancer cells, principally inhibiting aerobic glycolytic activity, by its effect on mitochondrially-bound hexokinase (HK). In such way LND could impair energy-requiring processes, as recovery from potentially lethal damage, induced by radiation treatment and by some cytotoxic drugs. A randomized study started in November 1983, to evaluate the efficacy of LND in association with radiotherapy as first line treatment in malignant gliomas, after surgical procedure. LND was also used in association with Lomustine (CCNU) at the moment of documented clinical and neuroradiological recurrence. At the present time 60 patients entered the study, and 47 are evaluable. Present preliminary results are not statistically significant, however indicate that LND tends to prolong the median survival time and the rate of one year survivors.