Cardiac progenitor cells (CPCs) are a promising autologous source of cells for cardiac regenerative medicine. However, CPC culture in vitro requires the presence of microenvironmental conditions (a complex array of bioactive substance concentration, mechanostructural factors, and physicochemical factors) closely mimicking the natural cell surrounding in vivo, including the capability to uphold reactive oxygen species (ROS) within physiological levels in vitro. Cerium oxide nanoparticles (nanoceria) are redox-active and could represent a potent tool to control the oxidative stress in isolated CPCs. Here, we report that 24 h exposure to 5, 10, and 50 μg/mL of nanoceria did not affect cell growth and function in cardiac progenitor cells, while being able to protect CPCs from H(2)O(2)-induced cytotoxicity for at least 7 days, indicating that nanoceria in an effective antioxidant. Therefore, these findings confirm the great potential of nanoceria for controlling ROS-induced cell damage.