Glioblastoma (GBM) is the most common malignant brain tumor. As it is highly vascularized, anti-angiogenic treatment strategies have been tested. Such treatment hinders radiological tumor monitoring. Here, we probed the potential of magnetic resonance elastography (MRE) to evaluate GBM treated with anti-angiogenic therapy. GBM was orthotopically implanted in 10 nude mice, of which 5 were treated with B20 anti-VEGF antibody. MRI and MRE were performed repeatedly and brains were harvested for histology afterwards. Anti-angiogenic treatment slowed tumor growth, affected contrast-enhancement and slowed down tumor softening. The phase angle Y expressing the solid/liquid ratio appeared to indicate tumor progression.