[3] When she was 3 years old, the family moved to San Juan, Puerto Rico, where she completed her primary and secondary studies at Colegio Puertorriqueño de Niñas, a secular private school for women.
[4] Del Rosario attended the University of Puerto Rico (UPR), Río Piedras campus, from 1931 until 1935, where she earned a bachelor’s degree in physical sciences.
[7][8][9][10] In 1943, Leticia del Rosario was hired as an Assistant Professor in the Department of Physics of the University of Puerto Rico, Río Piedras campus.
[4] At the time, Jaime Benítez Rexach was the chancellor, physicist Facundo Bueso Sanllehí was dean of natural sciences, and Amador Cobas was chair of the physics department.
[4] In the summer of 1949, she traveled to Oak Ridge National Laboratory (ORNL), sponsored by the Rockefeller Foundation, to participate in a training course on the use of radioisotopes for research in nuclear physics, medicine, and agriculture.
The topics discussed included plans to install nuclear reactors in Puerto Rico, for scientific research and power generation.
In 1961, she was director of a training program for physics high school teachers funded by the National Science Foundation.
[16][17] At UPR she was member of the Academic Senate and founder and president of the University Faculty Organization ("Organización de Profesores Universitarios").