Diffusion-weighted magnetic resonance imaging (DW MRI) was applied to the lyotropic lamellar phase of the dodecylammonium chloride/water system (DDACl/H2O). In the course of employing a well-known medical imaging method, namely, diffusion tensor imaging (DTI), the system morphology was assessed accurately ill the most straightforward way by two-dimensional visualization of eigenvectors associated with planar distribution of effective diffusion tensors throughout the whole slice with 40 mu m in-plane resolution. Long-range order was observed in the Studied lamellar phase, and morphology was best described by a combination of three- and one-dimensional diffusion.