The estimates of the duration of Kondratyev cycles in countries with different levels of technical and economic development are obtained. The regularity of the reduction in the duration of Kondratieff cycles are revealed, which increases more, when the corresponding Kondratyev cycle begins to form in them later. For each year of the displacement of the third cycle, the duration of the third cycle reduces by an average of 0.6 years. For each year of the displacement of the 4th cycle, the duration of the third cycle reduces by an average of 0.8 years. In countries — the leaders of the world economy in terms of labor productivity, the reduction in the duration of Kondratyev cycles does not take place. The regularity of reducing the length of Kondratyev cycles justifies the existence of the possibility of accelerated economic development.