Dilated cardiomyopathy (DCM) is characterized by the presence of left ventricular dilatation and contractile dysfunction [1-2]. Anatomically, the human heart is divided into four chambers, but the transcript and protein profiling of human myocardial tissue with DCM are not well understood [3-5]. Here, we performed high-throughput transcriptomic and proteomic analyses on human hearts from healthy control as well as end-stage DCM, which served as a systems-level perspective in characterizing cardiac biology and exploring DCM mechanism. Comparisons of the 9,219 identified proteins in four chambers of human hearts with deep sequencing data of the 14,880 transcripts indicated deep coverage of the proteome. The core proteome of healthy hearts was significantly enriched in biological functions including extracellular matrix organization, cytoskeleton organization, biosynthetic process signal transduction, ect. Comparing DCM hearts with healthy ones via iTRAQ-based quantitative proteomic analysis, the changing patterns in the left ventricle were more extensive and drastic compared to the other chambers in end-stage DCM, among which ECM organization, mitochondrial function and muscle contraction were the most enriched three GOBP terms. Furthermore, oxidative phosphorylation, calcium signal pathway, and carbohydrate metabolism were disturbed during DCM development. Our comprehensive proteomic and transcriptomic analyses presented precise quantification of potential signatures, signaling pathways, regulatory networks, and characteristic differences in each DCM chamber. Additionally, 8 secreted proteins were selected from the total 608 significant changed cardiac proteins, and further verified in a cohort of 53 DCM serums and 35 healthy serums via ELISA analysis (P<0.05). The combined use of Complement component C9, cathepsin B, dickkopf-related protein 3 and von Willebrand factor as serum biomarker panel showed high diagnostic potential in early detection of DCM. These integrated datasets provide diverse and rich resources for researches to investigate the molecular basis of heart physiology and pathology including cardiomyopathies.