Reactive oxygen species (ROS) are partially reduced oxygen molecules produced during cellular metabolism in all aerobic organisms including plants. ROS derivatives such as superoxide (O2–) and hydrogen peroxide (H2O2) cause several types of cell damage in plants. Chloroplasts and mitochondria are major sources of ROS because of photosynthesis and aerobic respiration in these organelles, respectively. Previously, our lab showed that light-grown maize plants have more damage in plastid DNA (ptDNA) and mitochondrial DNA (mtDNA) than dark-grown plants and that ptDNA and mtDNA levels decline during leaf development. Here, we hypothesize that increased damage to ptDNA and mtDNA in light-grown leaves is linked to increased ROS generation compared to dark-grown and germline stalk tissues. We used absorbance- and/or fluorescence-based assays to quantify levels of ROS in chloroplasts and mitochondria isolated from leaf and stalk tissues during seedling development. Our data suggest that light-grown leaf has more ROS than light-grown stalk, dark-grown leaf, and dark-grown stalk. Our findings indicate that highly damaged DNA is a consequence of ROS generation in light-grown leaves of maize. Overall, this research will help us further understand the oxidative damage caused by various reactive oxygen species during the development of maize plants.