We report the findings on serial diffusion-weighted MRI in a 29-year-old male with neuro-Behcet`s disease. Initial T2-weighted and fluid-attenuated inversion recovery images showed a hyperintense lesion in the brain stem. The lesion showed slight hyperintensity on diffusion-weighted images with no evidence of diffusion restriction on apparent diffusion coefficient maps. A follow up study after 7 months showed complete resolution of the brain stem lesion. Our findings indicate that diffusion-weighted imaging is a useful tool to differentiate acute exacerbation of neuro-Behcet`s disease from acute infarction, and therefore it helps in selecting the appropriate therapy.