The development of oat varieties for groats production is a topical issue, therefore the research goal was to study the influence of small grain percentage on groats yield and to evaluate the correlation relationship of this character with the quality indices. The research was carried out in the Grain Quality Laboratory of the Siberian Research Institute of Agri- culture from 2014 to 2016. The research objects were 20 oats accessions from Competitive Variety Trial Nursery of the Oats Selection Laboratory (Siberian Research Institute of Agricul- ture) including 14 filmy and 6 hulless oats accessions. The accessions were evaluated according to the methodology of the State Commission for Variety Testing. The study of dy- namic pattern of t ‘small grain percentage’ character in oats accessions showed that on 3-year average filmy accessions had low percentage of small grains (less than 5 %) - 0.2-4.1 %. Hulless oats accessions revealed unstable formation of this character over the years of research. For grain exit in filmy forms of oats considerable fluctuation of the indicator by years of research was characteristic; the difference between extreme values made 6.2-21.9 %, in hulless samples the exitof grain differed within 2.6-6.7 %. It was found out the sign of the share of fine grain had essential impact on all qualitative signs, but the extent of this influence depended on weather conditions of vegetative period. Especially close correlation of this connection was noted between this indicator and the signs of mass of 1000 grains and filminess, and at hulless samples this correlation was expressed more strongly, than in filmy. The share of fine grain was closely connected with grain exit, and in filmy samples this influence was expressed by strong return correlation, and in hulless samples this commu- nication was from weak to strong. These results testified that the development of standards and techniques of work on the assessment of quality indicators of grain was necessary for the assessment of hulless oats. It was established that by the sign the grain exit for further selection work could be recom- mended the following samples: among filmy Mutika 1147 and among hulless Inermis 1143, Inermis 1055.