The production of free radicals is the result of normal cellular metabolism. Free radicals are involved in innumerable different cellular and biological functions such as signaling, proliferation, cell death, aging, inflammation, etc. Under physiological conditions, the levels of reactive oxygen species (ROS) are strictly regulated by the cells. However, during stressful conditions such as oxidative stress, ROS levels increase causing damages to different molecules like DNA, lipids and proteins. Increased levels of ROS have been associated with a growing list of different diseases. In this protocol, we used MitoSOX and CellROX Green oxidative stress probes to label the intracellular ROS and detect the fluorescence using cell sorting and confocal analyses.