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Background and purpose The aim of the present study was to evaluate factors predicting the recurrence pattern determined by [ 18 F]FET-PET imaging in patients with newly diagnosed glioblastoma after combined radio-chemotherapy treated according to the EORTC/NCIC trial. Material and methods Seventy-nine patients with newly diagnosed GBM treated with radiotherapy plus temozolomide (75mg/m 2 /d) followed by adjuvant cyclic (5/28days) temozolomide (150–200mg/m 2 ) were retrospectively analysed. Recurrence patterns were assessed by means of positron-emission-tomography with [ 18 F]FET and additional MRI; in 54 patients MGMT methylation status was evaluated. Results Whilst 49.4% of the patients had an in-field recurrence, 12.6% an ex-field recurrence and 3.8% a recurrence at the field margin, 34.2% of the patients did not relapse during follow-up (median 595days). Considering all patients included in this study, 41.5% (12/29) of the MGMT methylated population had no relapse, 37.9% (11/29) had an in-field-recurrence and 20.7% (6/29) an ex-field/marginal recurrence, whilst 28.0% (7/25) of the MGMT unmethylated population had no relapse, 64.0% (16/25) had an in-field-recurrence and 8.0% (2/25) an ex-field/marginal recurrence ( p =0.15). Conclusions After the administration of temozolomide concomitant with and adjuvant to radiotherapy in patients with glioblastoma, the pattern determined by [ 18 F]FET-PET seems to be associated with MGMT methylation status.