The optimal treatment for recurrent high-grade gliomas is unknown and a standard of care does not exist. Re-irradiation with concomitant bevacizumab represents an option. Retrospectively, we analyzed a cohort of heavily pretreated patients (n = 14) with relapsing HGGs who underwent re-irradiation with conventional 3D-conformal or intensified modulated radiotherapy (IMRT). Ten of them received re-irradiation in combination with bevacizumab. The study population consisted of eight GBMs and six anaplastic gliomas. All patients had previously undergone irradiation for first-line therapy, including seven patients with radiochemotherapy with temozolomide. Patients without contraindications started with two infusions of bevacizumab (10 mg/kg of body weight every other week) prior to re-irradiation and continued through re-irradiation until progression. The median patient age was 45 years with a median Karnofsky performance scale of 70. The median dose of re-irradiation was 41.6 Gy [39-55 Gy]. The median physical cumulative radiation dose was 101.6 Gy [65-110.4 Gy]. The median PFS from re-irradiation was 5.1 months [1.6-17.4] based on clinical and RANO criteria. Median OS from re-irradiation was 9.0 months [6.4-17.8]. We detected radionecrosis due to advanced imaging in one patient. Other toxicities were expected and attributable well known side effects of bevacizumab. This retrospective study provides additional feasibility and safety data of conventional 3D-conformal re-irradiation and IMRT in combination with bevacizumab in relapsing high-grade gliomas.