The article examines doctrinal approaches of Russian criminal procedure science to the classification of violations of criminal procedure law that result in the exclusion of inadmissible evidence from criminal proceedings. The author substantiates the necessity of scientific systematization of procedural defects, conditioned by the absence of an exhaustive list of such violations in the Criminal Procedure Code of the Russian Federation and the dispersion of evidentiary requirements across multiple provisions. Conceptually different approaches to the systematization of violations proposed by leading Russian proceduralists are analyzed. The results of contemporary dissertation research are generalized, and multilevel systems of grounds for evidence inadmissibility are examined. The author concludes that there exists a stable core of classification models despite the multiplicity of methodological approaches, which reflects the complexity and multifaceted nature of the phenomenon of criminal procedure law violations resulting in the exclusion of inadmissible evidence in criminal proceedings.