A method that involves projecting the properties of organic parasites into the field of architecture, thereby allowing the identification criteria of architectural parasites to be determined, is considered in this article. The relations of architectural organisms are analyzed based on of the primary features of organic parasites, as a type of relationship between two organisms. The original system of identification and classification of architectural parasites is presented. The conditions and restrictions in the application of this identification are defined. In the course of the analysis, the defining properties of the architectural parasite were formulated, namely: dependency element — the parasite must be structurally dependent on the host; reconstruction — the parasite and its host must have different construction times and different authors; contrast — the parasite must be visually diverse from its host; volume proportion — the coefficient of the scale of parasite relative to the host should be tend to a minimum. Ulteriorly these signs will help more clearly understand the parasite-host relationship, determine the essence of architectural parasitism and create a method, that would help to cut off «pseudoparasites». Systematizing features were also formulated, some of which were borrowed from the field of biology. The data collection on systematizing features is a prerequisite to the analysis of architectural parasitism from the historical, urban-planning and architectural-compositional points of view in order to predict the development prospects of the direction.