Description: Subject of the study were 341 sheep from the Karnobat Fine Fleece breed, ownership of the Institute of Agriculture - Karnobat. The productivity of animals born between 2013 and 2017 was analyzed. The genealogical structure of the flock included 3 breeding lines - 777, 2081 and 1825. The main selection traits that were studies were: live weight at weaning, at 1.5 years and 2.5 years, wool yield and staple length at 1.5, 2.5 and 3.5 years, clean wool yield and clean fibre at 1.5 and 2.5 years. This information was collected from the Pedigree book of the farm. The data were obtained through standard methods and instructions provided in the Instruction for control of productive traits (2011), issued by the Association for Breeding Fine Fleece Sheep in Bulgaria. The following measurements were made: 951 measurements of live weight, 870 measurements of wool yield and staple length and 579 samples were analyzed for clean wool yield and clean fibre. The data were processed according to the variation statistics methods and adjusted for the influence of the year. The study on the Karnobat Fine Fleece breed reported a positive lineage effect for the 1825 line for live weight at 1.5 and 2.5 years - 54,100 kg and 59,230 kg and for staple length at all ages - 13.62, 11.52 and 11.40 cm. Animals from the 2081 line exhibited higher results for the wool yield trait - 7.950 kg and 7.280 kg, clean wool yield trait - 65.81 PROCENT and 66.50 PROCENT and clean fibre trait - 5.230 kg and 4.840 kg at 1.5 and 2.5 years. Minimal linear differentiation on the basis of live weight and wool productivity traits in sheep of the Karnobat Fine Fleece breed was found. Narrowed genetic diversity does not allow successful selection and genetic progress on the studied traits in the population