A brief review of magnetic structures determined by neutron-diffraction techniques is presented with particular emphasis on developments in the past few years. A number of recent experimental advances are described, including improvements in monochromators, the technique of neutron polarization analysis, and the profile-fitting method for analysis of neutron powder data. Theoretical aspects discussed are the application of magnetic symmetry and representation theory to the determination of magnetic structures. Magnetic structures of a wide range of materials of general interest are described. These include transition metal compounds with rock-salt, rutile, and hematite-type structures, spinels, perovskites, transition metals and alloys, rare-earth metals and alloys, actinide compounds, and compounds with one- and two-dimensional magnetic properties. Up-to-date data for about 200 of these compounds are summarized in tabular form.