Cardiac organoids are increasingly used as humanized models to study complex cardiac pathologies requiring very mature cardiomyocytes. The production of relatively large cardiac organoids requires an increasing supply of oxygen and nutrients as they mature. Vascularization of hiPSC-derived cardiac organoids is therefore essential to supply gases and nutrients to cardiomyocytes and other cells types like cardiac fibroblasts. HUVECs are commonly used but do not completely exhibit adequate endothelial phenotype for intra-organoid vasculature formation. The production of mature endothelial cells from hiPSC is therefore essential. We have developed a unique protocol for producing endothelial cells from hiPSCs with a high degree of maturity: endothelial markers CD31, CD144, vWF, formation of tight junctions, ability to fix inflammatory cells under TNFa treatment, formation of capillaries, mature coagulation profile. The use of these endothelial cells in combination with cardiomyocytes and fibroblasts into multicellular organoids shows capillary organization in the structure with a rather internal localization of CD31 marking. Troponin T and alpha actinin markers show that the sarcomerization of cardiomyocytes is much more structured in cardiac organoids after 3 weeks of culture. This type of organoid can therefore be very interesting for editing cardiac pathologies linked in particular to mutations in sarcomere genes (FLNC, MYBPC3, MYH7).