In recent years much attention has been focused on the functional importance of 5-HT5, 5-HT6 and 5-HT7 receptors in the pathogenesis of neuropsychiatric and other diseases. In this connection, intensive studies with ligands of these receptors are currently in progress. Recognition of the structural characteristics responsible for the binding of a ligand molecule to an appropriate receptor, and development of an active complex have reached an advanced stage in the search for selective compounds. This review was undertaken to summarize the results of structure-activity relationship studies with ligands of 5-HT5, 5-HT6 and 5-HT7 receptors. Additionally, some data on localization, pharmacological properties and the functional role of those receptors were reported.