Abstract Body: Diabetes mellitus is an important risk factor for coronary artery disease, heart failure, and cardiomyopathy, contributing to atherosclerosis as well as structural and functional cardiac changes. Patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) hold great potential for investigating cellular mechanisms and serving as a platform for drug discovery. In the present study, beating iPSC-CMs were generated from peripheral blood mononuclear cells of a healthy control (a 27-year-old female) and uncontrolled diabetic patients with ischemic cardiomyopathy (ICMP) and non-ischemic cardiomyopathy (Non-iCMP). The 56-year-old male patient with ICMP had significant three-vessel coronary artery disease with a reduced ejection fraction (EF) of 35% and a hemoglobin A1C level of 9.6%. The 62-year-old male patient with Non-iCMP had a TTN gene mutation, no coronary artery disease, a reduced EF of 25%, and a hemoglobin A1C level of 10.5%. Electrophysiological properties were recorded from the three iPSC-CMs using whole-cell patch-clamp techniques and analyzed. More than 70% of the cells exhibited ventricular-like action potentials (APs), suggesting that these cells closely mimic the electrical properties of ventricular cardiomyocytes. Compared with iPSC-CMs from the healthy control, iPSC-CMs from ICMP and Non-iCMP patients exhibited significantly higher amplitude, prolonged action potential duration at 80% repolarization (APD80), and reduced maximum diastolic potential (MDP) (Table). RNA sequencing of the three iPSC-CM groups was performed, followed by differentially expressed gene (DEG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. DEG analysis revealed significant changes in genes related to fibrosis, cardiotoxicity, inflammatory response, extracellular matrix adhesion molecules, and atherosclerosis in iPSC-CMs from ICMP and Non-iCMP patients compared with iPSC-CMs from the healthy control. KEGG pathway analysis showed that significantly upregulated genes were associated with complement and coagulation cascades and cholesterol metabolism in ICMP iPSC-CMs, while extracellular matrix-receptor interactions and focal adhesion pathways were significantly upregulated in Non-iCMP iPSC-CMs compared with the healthy control. These findings indicate that iPSC-CMs from ICMP and Non-iCMP patients may serve as a valuable platform for modeling diabetic cardiomyopathy, investigating cellular mechanisms, and facilitating drug discovery.