Scientific observation was conducted in the commercial trip on the long-liner "Simeiz", operating under the Ukrainian flag, in the south-western Atlantic Ocean outside the exclusive (marine) economic zones of the foreign states (FAO statistical area 41) in the period from December, 11, 2007 till September, 10, 2008. Samples of crabs selected from bycatch during target fisheries for Patagonian toothfish Dissostichus eleginoides were selected on Patagonian slope (subarea 41.3.1) between 42 and 47 ° S on depths 700-2000 m. Catches of Paralomis formosa did not exceed 25 kg per a long-line set. Crabs occurred on depths of 984-1810 m. The length карапакса самцов crabs made 2,1-8,9 sm, the weight of-4-383, average length and weight самцов were equaled 7,1±0,02 sm and 207,0±3,6 accordingly. The carapace length of females varied within 3,0-8,2 cm, the body weight changed within the limits of 12-224 g, the average length and weight of females was 7,1±0,19 cm, and 108,0±1,7 g, accordingly. Sex ratio was 1:1 in the period from April till May, and 2:1 in the period from June till September, males prevailed. Reproduction was observed in crab population: spawning of eggs on pleopods and their incubation. Shells of the most crabs were clean and firm or with a small amount of parasites. The data on the distribution of crabs in area of toothfish fishery on the Patagonian continental slope were given.