We obtained the full-length cloning and characterized two GnRH receptors (GnRHRs) from brain/pituitary tissue of pejerrey fish. Both presented the conserved features of this family of receptors. The GnRHR expression patterns showed that both receptors were widely expressed in the central nervous system and peripheral organs, suggesting that these GnRHRs could be mediating different functions besides reproduction. Phylogenetic analysis performed by alignment of the three extracellular loop sequences (ECLs) showed that these molecules segregate into two main clades corresponding to GnRHR types I and II.