Based on the gross anatomic examination of 218 adult female reproductive tracts, we characterised the reproductive biology of the wild collared peccary in the Northeastern Peruvian Amazon. Collared peccary apparently breed year round in the Northeastern Peruvian Amazon and the number of pregnant females was 92 (42.2%). Estimations suggest 1.12 births/year and a yearly reproductive production of 1.98 piglets per pregnant female. Collared peccary females presented a mean ovulation rate of 2.25 ± 0.58 CLs, a litter size of 1.77 ± 0.48 embryos or foetuses and a reproductive wastage of 0. 45 ± 0.65 (21.3%) oocytes or embryos per pregnant female. A phenomenon of embryo migration was observed in 31.8% of pregnant females. This study provides reproductive information that should be taken into account in management plans. © 2010 Springer-Verlag.