Age determination of the Patagonian (Dissostichus eleginoides) and Antarctic toothfish (Dissostichus mawsoni) is conducted using otoliths, collected while carrying out the scientific program on board the Ukrainian vessel “Simeiz” in the Northern part of Weddell Sea (statistical Subarea 48.2) in March 2015. 124 otolith pairs of Dissostichus mawsoni and 87 otolith pairs of Dissostichus eleginoides were sampled; one otolith from each pair was used for age determination. Preliminary results of age determination of the caught fish showed that, in the studied fishing area, specimens of older age groups prevailed: their age ranged from 15 to 35 years for both species.