The presented study assesses the economic efficiency of reactive innovations in import substitution. Aim. The study aims to substantiate a model for the assessment of the economic efficiency of reactive innovations. Tasks. The present study determines the feasibility of developing a model for assessing the economic efficiency of reactive innovations and the potential for developing specialized methods for the economic assessment of reactive innovations implemented as part of import substitution measures. Methods. The methodological basis of the study comprises the scientific concepts of economic theory, innovation theory, and efficiency theory. This study also uses general scientific methods, such as systems and complex approach, economic and statistical analysis, to substantiate theoretical assumptions and rationalize the conclusions. Results. A substantiated and consistent method for the assessment of the economic efficiency of reactive innovations is proposed, based on the calculation of the relative value of the cost of scientific and technical or consumer characteristics for the consumer, that is, the correlation between the cost of an innovation to its consumer and the index of scientific and technical or consumer characteristics that serve as quantitative estimates of the scientific and technical and consumer effects, respectively. Conclusion. At present, the entire Russian economy faces the need for extensive implementation of reactive innovations in order to substitute industrial goods that can no longer be procured from traditional foreign suppliers due to either unavailability or non-merchantability. At the same time, it is necessary to select and assess innovations at early stages of project development, where assessment should account for the commercial, consumer, scientific, and technical effects, which raises the issue of developing specialized methods for the economic assessment of reactive innovations.