There are 17 described species of Eleutherodactylus in Puerto Rico, some more common than others. The use of harmonics as a means of vocalization has been little studied in the Caribbean. As part of a long-term study of the evolution of sonic communication in Puerto Rican Eleutherodactylus frogs, we document the use harmonics in three common but distinct Puerto Rican endemic species: E. coqui, E. antillensis, and E. brittoni. This study focuses only on the description of these vocalizations using computer software not on the behavioral implications of these vocalizations.