The article is devoted to the consideration of the foreign policy of the axis of "socialism of the XXI century" through the prism of the historical anti-imperialist traditions of the Comintern. The author clarifies the meaning of the anti-imperialist struggle in the tradition of Marxism, the Second International and the teachings of V. I. Lenin. The article shows that both the ideology and the practical activities of the III International in 1919-1943 were built on the basis of the principles of anti-imperialism, which was one of the essential features of the Comintern. Specific examples, including those related to Latin America, show the significance of the anti-imperialist strategy before the functioning of the Third International. Also in the scientific article, the author refers to the historical experience of the anti-imperialist foreign policy of the leftist regimes in Latin America during the Cold War, considering the cases of Cuba, Chile and Nicaragua as examples. The article concludes about the fundamental importance of the anti-imperialist line and solidarity in the activities of the Latin American left movement in the 21st century, as evidenced, in particular, by the factor of the Sao Paulo Forum. The author comes to the conclusion that, in general, the countries of the axis of "socialism of the 21st century" are implementing a left-wing foreign policy with a very powerful anti-imperialist component in modern geopolitical conditions. At the current stage, Cuba and Venezuela are the most influential and authoritative representatives of this course. In the article, the author refers to the cases of modern foreign policy of Cuba, Venezuela, Bolivia and Nicaragua, considering anti-imperialism in their foreign policy primarily as a policy against US actions. In conclusion, the author shows which traditions of the Third International are de facto present in today's policy of the leftist Latin American regimes.