The dusky catshark Bythaelurus canescens is a deep-sea shark caught as bycatch along the Chilean coast in the deep-sea crustacean, the yellownose skate Dipturus chilensis and the Patagonian toothfish Dissostichus eleginoides fisheries.The objective of the present study was to describe the reproductive characteristics and embryonic development of B. canescens. A total of 165 specimens (75 females and 90 males) were obtained between June and December 2006. The sex ratio of females to males was 0.8:1; total length (TL) ranged from 23.7 to 76 cm (mean 43.95 ± S.E. 12.92 cm) for females, and 23 to 68 cm for males (44.65 ± 10.96 cm). The reproductive mode of B. canescens is oviparity, containing a single egg capsule in each uterus.A total of 94 egg capsules were obtained, 24 in the uterus of gravid females and 70 collected from the sea bottom off Valparaíso, Chile, with a mean size of 60.7 ± 1.3 mm. From the collected egg capsules, a total of 18 embryos with sizes ranging from 1.4 to 8 cm TL (4.2 ± 1.8 cm) were extracted and seven stages of embryonic development were described based on morphological characteristics. Embryos at a size of 6 cm TL have morphological adult characteristics and at 8 cm TL, close to parturition, their yolk sac is reduced to 1 cm in diameter.