This chapter explores the pathology of blood vessels and cardiac diseases, focusing on arterial and venous disorders and various cardiac conditions. Key topics include the pathogenesis and clinical implications of atherosclerosis, hyaline arteriosclerosis, and hyperplastic arteriolosclerosis, which significantly contribute to vascular complications. Monckeberg’s medial calcific sclerosis and polyarteritis nodosa are discussed as examples of less common but clinically significant vascular conditions. Inflammatory diseases such as giant cell arteritis and temporal arteritis are highlighted, along with their diagnostic criteria and treatment strategies. The chapter also examines venous conditions, including the pathology of varicose veins and thrombotic thrombocytopenic purpura (TTP). Cardiac-related topics cover advancements in valve replacement techniques, including mechanical valve prostheses, porcine valve bioprostheses, and innovations in pacemaker technology. The mitral annulus and its involvement in disease processes are detailed, with an emphasis on morphological changes. By integrating microscopic findings with clinical correlations, this chapter provides a comprehensive overview of vascular and cardiac pathologies, equipping readers with essential knowledge for diagnostic and therapeutic purposes.