The paper presents a general approach to computer-aided recognition problems as identification of relations satisfied by the objects under examination. Pattern recognition is considered as a binary relation of objects’ similarity. Five other types of binary relations: matching, adjacency, distinction, ordering and attachability are described and illustrated as backgrounds of other types of recognition problems and procedures. An extension of the relations-based approach to recognition problems on higher-order relations, as well as on algebraic combinations of relations is described. The role of a proper similarity measure in solving a given relation recognition problem is described. Finally, a possibility of significant extension of the investigation area of computer-aided objects recognition is concluded.