This study reports genetic parameters for yearling and adult wool and growth traits, and ewe reproductive performance. Data were sourced from an Uruguayan Merino flock involved in a long-term selection program focused on reduced fiber diameter (FD), and increased clean fleece weight (CFW) and live weight (LW). Pedigree and performance data from approximately 5,700 mixed-sex yearling lambs and 2,000 mixed-age ewes born between 1999 and 2019 were analyzed. The number of records ranged from 1,267 to 5,738 for yearling traits, and from 1,931 to 7,079 for ewe productive and reproductive performance. Data on yearling and adult wool traits, LW and body condition score (BCS), yearling eye muscle area (Y_EMA), and fat thickness (Y_FAT), and several reproduction traits were analyzed. The genetic relationships between FD and reproduction traits were not different from zero. Moderate unfavorable genetic correlations were found between adult CFW and ewe lifetime reproduction traits (-0.34 ± 0.08 and -0.33 ± 0.09 for the total number of lambs weaned and total lamb LW at weaning, respectively). There were moderate to strong positive genetic correlations between yearling LW and all reproduction traits other than ewe-rearing ability (-0.08 ± 0.11) and pregnancy rate (0.18 ± 0.08). The genetic correlations between Y_EMA and reproduction traits were positive and ranged from 0.15 to 0.49. Moderate unfavorable genetic correlations were observed between yearling FD and Y_FAT and between adult FD and BCS at mating (0.31 ± 0.12 and 0.23 ± 0.07, respectively). The genetic correlations between adult fleece weight and ewe BCS at different stages of the cycle were negative, but generally not different from zero. This study shows that selection for reduced FD is unlikely to have any effect on reproduction traits. Selection for increased yearling LW and Y_EMA will improve ewe reproductive performance. On the other hand, selection for increased adult CFW will reduce ewe reproductive performance, whereas selection for reduced FD will negatively impact body fat levels. Although unfavorable genetic relationships between wool traits and both FAT and ewe reproductive performance existed, simultaneous improvements in the traits would occur using appropriately designed indexes.© The Author(s) 2023. Published by Oxford University Press on behalf of the American Society of Animal Science.RamosZullyZSchool of Agriculture and Environment, Massey University, Palmerston North 4410, New Zealand.GarrickDorian JDJSchool of Agriculture and Environment, Massey University, Palmerston North 4410, New Zealand.BlairHugh THTSchool of Agriculture and Environment, Massey University, Palmerston North 4410, New Zealand.De BarbieriIgnacioIEstación Experimental INIA Tacuarembó, Instituto Nacional de Investigación Agropecuaria, Tacuarembó 45000, Uruguay.CiappesoniGabrielGEstación Experimental INIA Las Brujas, Instituto Nacional de Investigación Agropecuaria, Canelones 90100, Uruguay.MontossiFabioFEstación Experimental INIA Tacuarembó, Instituto Nacional de Investigación Agropecuaria, Tacuarembó 45000, Uruguay.KenyonPaul RPRSchool of Agriculture and Environment, Massey University, Palmerston North 4410, New Zealand.eng772787European Union's Horizon 2020INIA_CL_38: RumiarNational Institute of Agricultural Research of UruguayMassey University, New ZealandNational Agency for Investigation and Innovation of UruguayJournal ArticleUnited StatesJ Anim Sci80030020021-8812IMPregnancySheepgeneticsAnimalsFemaleWoolReproductiongeneticsPhenotypeSheep, DomesticAdipose TissueWeight GainFiber diameter (FD), clean fleece weight (CFW), live weight (LW), and reproductive performance are important traits in Merino flocks. This study estimated the genetic parameters for a range of production traits and ewe reproductive performance. Data from approximately 5,700 mixed-sex yearling lambs and 2,000 mixed-age ewes born in a single Uruguayan Merino flock were analyzed. There were generally favorable (positive) genetic correlations between LW and reproduction traits. The genetic relationships between FD and reproduction traits were generally negligible. In addition, moderate unfavorable (negative) genetic correlations were found between adult CFW and ewe reproduction traits. This study indicates that selecting finer fleeces will yield little to no change in ewe reproduction traits, whereas heavier fleeces are related to reduced ewe reproductive performance. On the other hand, genetically heavier yearling ewes will display greater reproductive performance.