Traditionally, inbreeding has been estimated from pedigree-based information. Nevertheless, in the last years the interest for estimating inbreeding using genomic information has considerably grown. The objective of this study is to evaluate whether inbreeding estimated from ROHs or calculated on a SNP-by-SNP basis provide an accurate measure of inbreeding. The data set available included individuals from French dairy sheep breeds and subpopulations (Basco-Béarnaise, BB; Manech Tête Noire, MTN; Manech Tête Rousse, MTR; Lacaune Confederation, LACCon; and Lacaune Ovitest, LACOvi). Those animals were genotyped with the Illumina OvineSNP50 BeadChip. After filtering, the genomic data included 38,287 autosomal SNPs and 8,700 individuals. Pedigree from those genotyped animals comprised 72,803 animals. Genome-based inbreeding was higher than pedigree-based inbreeding. This can be explained considering that pedigree-based inbreeding assumes that loci are neutral and it does not consider the potential bias resulting from selection. The highest rates of increase in inbreeding per generation were observed when using pedigree (0.0022 – 0.0099; BB, MTN and LACOvi) and ROHs (0.0022 – 0.0046; MTR and LACCon). The lowest rates of increase in inbreeding per generation were observed when calculating inbreeding on a SNP-by-SNP basis (0.0016 – 0.0044), except for LACOvi where the lowest rates were also observed with ROHs (0.0014). Both genome-based measures rank breeds and subpopulations in the same order regarding the effective population size: LACOvi (357), LACCon (227 – 313), MTR (109 – 200), MTN (81 – 179) and BB (59 – 114). Effective population size obtained from pedigree information provided similar estimates. ROHs yield a correct estimate of inbreeding at the genomic level and make it possible to identify specific IBD regions. These regions can be used to improve mating decisions and to minimise the unfavourable effects of inbreeding. Work financed by the ARDI project of Poctefa program (European Union FEDER funds).