He was born on 13 September 1928 in Lima, Peru to José Carlos Mariátegui La Chira and Anna Chiappe Iacomini, an Italian woman.

It was exactly with his companion of bench at the School San Luis, the Father Gustavo Gutiérrez, that took in parallel sciences and humanities, enjoying philosophy classes, as those of Mariano Iberico and also they studied the first year of medicine; both being also college students representatives.

with the thesis "Psychopathology of the experimental poisoning with dietilamida of acid d-lisérgico (LSD)" and he distinguished with the contenta for having obtained the highest grade during his studies, nevertheless he decided to stay in Peru.

In 1957 it was gotten up to teaching and she was head of clinic in the chair of Psychiatry that directed Honorio Delgado and like delegate of the professors of that category, integrated in 1960 the faculty board.

In 1963 he published his first book "Studies of Social Psychiatry in Peru" with Baltazar Caravedo, Humberto Rotondo and in 1969 "Psychiatric Epidemiology of an Urban District of Lima" with Berna Alva and Ovidio de Leon.

Javier Mariátegui always emphasized by his intellectual loyalty and great admiration by people who marked their academic formation, much of the representative figures of Peruvian medicine as well as by some of his university teachers.

He wrote periodically and published books in tribute of illustrious intellectuals and Peruvian physicians, some that considered important to rescue as well as others with which it maintained a personal communication.