Purpose. The clinical usefulness of diffusion-weighted imaging (DWI) was evaluated in patients with brain abscesses in comparison to patients with cystic brain tumors. Material and methods. Five patients with surgically confirmed brain abscesses underwent beside a brain MRI examination with contrast media application diffusion weighted imaging. Apparent diffusion coefficients (rADC) in three orthogonal diffusion gradient were calculated.The same protocol was used to examine 5 patients with cystic brain tumors. Results. Showing an rADC of 0.33 x 10(-3)/mm(2)/s abscesses have a highly restricted diffusion in, comparison to cystic brain tumors with an rADC of 1.67x10(-3)/mm(2)/s. Conclusion. Diffusion weighted imaging is a useful diagnostic tool in the work up of brain abscesses.