In 2011 and 2012 in Subarea 88.3 research fishing for toothfish has been conducted by Russia. In 2011 fishing was carried out by Russian longliner “Sparta” out and in 2012 it was longliner “Chio Maru 3”. Research program was performed by scientific observers from VNIRO (Moscow, Russia) and YugNIRO (Kerch, Ukraine). Totally, during the work period 44 longlines were set at a depth from 625 to 2336 m. Total number of set hooks amounted 171096. In 2011 research fishing covered SSRU B, C and D, and in 2012 ice conditions were much worse and longlines were set only in SSRU C. Collected in research fishing data contributes to the achievement of the main objectives of research for the data-poor area: estimate of number index, evaluation of fishing capacity of Subarea 88.3, preparation of hypotheses about the ratio of fish in the area and the total stock as well as studying of biological parameters associated with productivity (SC-CCAMLR-XXX/5, par. 2.26-2.29). Toothfish's biomass was calculated by the accepted in SC-CCAMLR-XXX/5 p.2.40 (ii) formula. Value of toothfish`s stock by SSRUs and all details of stock assessment methods are described in the present work.