Technologies, methods and instruments of isotope technique as well as their use in national economy, in particular in industries, are the result of vast activities in the fields of research, designing and primary manufacture. The efficiency of the application os isotope technique, especially its economic efficiency, depends both on the extent, to which this technique is being introduced, and on the average economic effect per unit (instrument, method, or technology) applied in various brandies of national economy. By comparison of the costs of investigations conducted in the field of isotope and radiation techniques, as well as of the total economic effect gained in a series of countries, the general economic efficiency of isotope investigations was determined. The analysis of the structure and dynamics of the said efficiency coefficient as arrived at in the various countries over a long period was the main subject of the present work.