An intricate network of cardiac blood and lymphatic vessels provide cardiac tissue with oxygen and nutrients and eliminate excess fluid from the interstitium. Lymphatic vessels are required to maintain normal heart function and their blockage or destruction leads to cardiac edema, fibrosis and inflammation. Despite their critical roles in physiology and pathology, little is known about lymphatic vessel growth and development in the heart. Building on our recent work on coronary vessel development, we have described the formation of the lymphatic vasculature system in adult zebrafish. Lymphatic endothelial cells reside on the bulbus arteriosus until 3 months of age when they sprout on to the ventricle, preferentially migrating down the coronary arteries. Over several weeks these initial sprouts form vessels that are in close proximity to the coronary arteries and extend branching vessels that partially cover the ventricle. We are currently investigating the role of CXC-signaling in guiding this process and the potential role lymphatic vessels play in heart development and regeneration.