The article examines pathological and diagnostic terms in Uzbek and Russian from the viewpoint of thematic classification and nominative modelling. Medical terms are treated not only as specialized lexical units, but also as instruments of professional communication, clinical reasoning and doctor-patient interaction. Pathological terms are analyzed as names of diseases, symptoms, pathological processes and complications, while diagnostic terms are interpreted as units denoting examination methods, clinical findings, measurements and final medical conclusions. The comparison shows that both languages use international Greco-Latin elements, native word-formation resources, attributive combinations and multi-component terminological phrases. Uzbek tends to combine international bases with explanatory native components, whereas Russian more actively uses adjectival and genitive models.