Objective: To evaluate the additional diagnostic value of diffusion and perfusion MRI in the differentiation of glioblastoma multiforme (GBM) and solitary brain metastasis. Patients and methods: This retrospective study included 24 patients with histologically proven brain tumors who underwent conventional MRI with analysis of diffusion (DWI) and perfusion (PWI) MRI findings of each tumor. The Apparent Diffusion Coefficient (ADC) values were calculated in the minimum (ADC-MIN), mean (ADC-MEAN), and maximum (ADC-MAX) in all the tumors and the peritumoral regions. The PWI data was expressed as maximum regional cerebral blood volume (rCBV) of the tumors and peritumoral regions. Results: After adding diffusion and perfusion to conventional MRI findings, we found that the accuracy of differentiation between glioblastoma multiforme (GBM) and solitary metastasis increased from 70% to 90%. Results: There is a significant difference in DWI signal intensity between GBM and metastatic tumors (P 0.05). The ADC values of GBM were lower than that of metastatic tumors. On perfusion MRI, the maximum rCBV of the peritumoral region (rCBVP) of GBM was higher than that of brain metastases (P 0.001). Conclusion: The addition of diffusion and perfusion to the MRI protocol increases the accuracy of differentiation between GBM and solitary brain metastasis and should be considered routinely.