Reactive oxygen species (ROS) are reactive derivatives of O2 metabolism produced by all types of vascular cells. ROS play an important role in both physiological and pathological situations by acting as intracellular signaling molecules which regulate vascular function and structure. Accordingly, oxidative stress is implicated among other processes in inflammation, hypertrophy, migration, growth/apoptosis and extracellular matrix protein turnover which are important processes involved in vascular remodeling in cardiovascular diseases. In the cardiovascular system, the major source of ROS is the NADPH oxidase family of enzymes composed by seven members where NOX-1 and NOX-4 are the main isoforms in vascular smooth muscle cells. This review highlights the importance of NOX-derived ROS in vascular biology and focuses on the potential role of oxidative stress in vascular remodeling