The Body Condition Score relates to livestock reproduction, such as estrus, pregnancy, the birth process, and the condition of lambs. If the lamb has a bodyweight exceeding the ideal body weight, the animal will experience reproductive disorders to metabolic diseases. However, if the mother sheep has a body weight less than ideal, it can disrupt the reproductive system, affecting the symbol interval. This research aims to find out the relationship between Body Condition Score and the reproductive performance of sheep in Langkat Regency, namely Service Per Conception and Lambing Interval. The study design is Deskriptif analysis. Research conducted in Langkat Regency, Indonesia, between November 2022 and January 2023.The method used in this research is a case study, namely by collecting primary and secondary data. The observed variables are Body Condition Score (BCS) and Lambing Interval. The results of the study are The value of the Body Condition Score with the Lambing Interval regression equation Y = 15.677-0.818X. (R2) 12.8%. (r) of 0.358. The relationship between Body Condition Score and Calving Interval is positive, with an R2 value of 12.8%. The conclusion of the research is The relationship between the lambs Body Condition Score (BCS) and the Lambing Interval had a good correlation with an average Calving Interval ranging from ≤8 to 9 months.