This study aimed to determine the genetic variability of 203 specimens of doncella Pseudoplatystoma punctifer from seven natural populations of the Peruvian Amazon through the analysis of 8 microsatellite loci. The results show a high genetic variability in the species (113 alleles found, with an average of 13.14 alleles per locus). The correspondence factor analysis showed the existence of genetic differentiation between some populations of this species, in addition, the results of the fixation index (FST), Number of migrants per generation (Nm) and genetic distance showed that the populations of Madre de Dios and Nanay present the greatest genetic differences between them (FST = 0.115, Nm = 1.93; D = 0.349) and also with the rest of the populations (Madre de Dios: FST varies from = 0.039 to 0.057; Nm = 4.16 to 6.24; D = 0.135 to 0.174; Nanay: FST varies from = 0.060 to 0.080, Nm = 2. 8...