In 1930, the government of Leguia was ended by a coup led by General Luis Miguel Sánchez Cerro, who had significant popular acceptance since the discrediting of President Leguía after the crisis of 29. It happened a fascist-inspired government which came into open conflict with the APRA and communist factions. The government of Sanchez Cerro culminated in his assassination by a militant APRA during a military review to be sent to the conflict in Leticia.

In 1932, a group of citizens of the Colombia-Peru border area, in view of the demands made by the Casa Arana and monitors, are taken by assault on the city of Leticia, being defeated by the weapons in Colombia Indeed, life is lost 200 to 250 soldiers, and upheld the borders between the two states as a final solution to the conflict in the treaty Lozano-Salomón.2

In June 1941, the Ecuadorian army attacked Zarumilla area in Peru's northern border, sparking the so-called War 41. Peru had formed a unit of paratroopers in the area and made use of it in the first battle in the Southern Hemisphere where airborne troops intervened, which led to the taking of Puerto Bolivar on July 31, 1941, the month when the cessation of military operations. The Peruvian army was in possession of part of the Ecuadorian province of El Oro, on the Pacific Ocean and parts of the province of Loja and reasserted its control over territories on the eastern Amazonian Ecuador claimed the sovereignty. In Rio de Janeiro (Brazil) signed the Protocol of Peace, Friendship and Boundaries of Rio de Janeiro on January 29, 1942, which ended the armed conflict. Sprout a new conflict in 1995 Cenepa War, which led to the signing of the Itamaraty (Brazil) where Peru, where the Peruvian-Ecuadorian border conflict was finally completed.

The return of democracy is also the return of Manuel Prado y Ugarteche the government for the second period. Faced with criticism of his handling of the economy as prime minister appointed Peter G. Beltran, who balanced public finances and stabilizes the Peruvian currency. Prado's defense makes the controversial results of the elections of June 10, 1962 provides a new military coup, although he (led by Nicolás Lindley López and Ricardo Pérez Godoy) was a reformist to the point that outlines land reform . The government brief new elections in 1963 to win the centrist Fernando Belaunde Terry (Popular Action). Belaunde promotes public works within the country and tries to carry out a series of reforms (including a comprehensive agrarian reform), but is permanently boycotted by the Congress by the coalition of the APRA party and the National Union Odria. Inside the country, social conflicts happen and the action of communist-inspired guerrillas.