Background: Genetic selection for meat production performance of broilers concomitantly causes excessive abdominal fat deposition, accompanied by several adverse effects, such as the reduction of feed conversion e ciency and reproduction performance. Our previous studies have identi ed important genes regulating chicken fat deposition, using the Northeast Agricultural University broiler lines divergently selected for abdominal fat content (NEAUHLF) as an animal model. However, the molecular mechanism underlying fat deposition differences between fat and lean broilers remains largely unknown.Results: Here, we integrated the transcriptome (RNA-Seq) and quantitative proteome (isobaric tags for relative and absolute quantitation, iTRAQ) pro ling analyses on abdominal fat tissues from NEAUHLF chicken lines. Differentially expressed genes (466 DEGs) and proteins (231 DEPs) were identi ed, and enriched in pathways related to fatty acid metabolism, fatty acid biosynthesis, glycerophospholipid metabolism, and PPAR signaling, and in pathways mainly involved in protein processing, endocytosis and lipid metabolism, respectively. Moreover, several key DEGs and DEPs involved in long-chain fatty acid uptake, in situ lipogenesis (fatty acid and cholesterol synthesis), and lipid droplets accumulation were discovered, and most of them were up-regulated in the fat line, after integrated transcriptome and proteome analysis.Conclusions: Together, our ndings provided a novel insight into abdominal fat content discrepancy between the fat and lean chicken lines.