The accumulated retrospective experience with glioblastoma multiforme was reviewed. Data were extracted from 17 reports in the literature, comprising 2532 patients. Survival curves were constructed for 1561 selected cases that did not include limited surgery and/or astrocytoma Grade III. The median survival after operation for the 1561 patients was 6 months, and only 7.5% lived 2 years. The survival curve is exponential in shape; calculation of its rate constant as well as extrapolation on a least squares regression line for the semilogarithmic plot of the data both predict 3- and 5-year survival rates of 1.7 and 0%, respectively. Curves were also plotted for patients who were treated by operation alone (6 study groups, 349 cases), operation plus radiation (11 groups, 568 cases), and operation plus radiation plus chemotherapy (5 groups, 146 cases); the median survival times for the three groups were 4, 9.25, and 10 months, respectively. It was concluded that (a) all curves converge at 18 to 24 months, irrespective of treatment; (b) radiotherapy is the decisive treatment during the first 18 months; (c) survival can be predicted by adopting an exponential model; and (d) prospective studies are required to detect the marginal benefits of current therapies.