Tiredness may be caused by the brain injury due to the tumor or the treatment in patients with glioblastoma multiforme (GBM). Some patients describe a sense of tiredness particularly after radiation or oral chemotherapy. To evaluate tiredness level of patients with GBM during preoperative, postoperative and radiotherapy we here eamined a sample of 38 patients. Data were collected over six months in a neurosurgery clinic. Patients assigned to Group I were given a booklet and information about radiotherapy, oral temozolomide and tiredness. Group II received only the booklet. The chi-squared test were used to determine differences in tiredness between Group I and Group II, with Spearman's correlation for post-radiotherapy results (3 and 6 months postoperative). In conclusion, the level of tiredness was assessed to be significantly better in Group I than in Group II. Levels of tiredness in patients with GBM were greatly affected by the radiotherapy and oral chemotherapy (temozolomide).