Relevance. Breeding work in animal husbandry can be successful if in result animals with high rates of productivity, required from them economically useful features (EUF), are obtained. Obviously, it is necessary to analyze several EUFs for qualitative assessment of animals. Recently, the knowledge of the regularities of individual development of the organism and their interrelation has become more and more important, it's research is an urgent task. The study of these regularities or combinations between individual phenotypic traits will serve as the basis for the development of a better system of breeding work in sheep breeding. Methodology. The studies were carried out in the Collective stud farm named after Lenin, Stavropol Territory. The object of the research were breeding records of primary zootechnical registers for the last 5 years on elite and first-class animals of fine-wool sheep breeds – Russian meat merino and Soviet merino; their live weight, quantitative and qualitative indicators of wool productivity of different sex and age groups were studied. Results. In our researches it was established that the connection between the length of wool and the trimming both on the group of adult ewes and on the yearlings of Russian meat merino sheep was relatively big – from r = + 0.425 to r = + 0.594 and of the Soviet merino – from r = + 0.280 to r = + 0.592 with high reliability of sampling correlation coefficients in both cases (P < 0,01 and P < 0,001); the correlation of wool cutting in physical weight with indicators of pure fiber turned out to be high – equal to + 0,766 in sheeps of Russian meat merino breed.