UV radiation damage DNA and can trigger Apoptosis in animal cells. Using A. thaliana we have shown that UV radiation can induce apoptotic-like changes at the cellular level and that an UV experimental system was relevant to the study of Programmed Cell Death (PCD) in plants. UV induction of PCD requires light and a protease cleaving the caspase substrate Asp-Glu-Val-Asp (DEVDase activity) is induced within 30 minutes and peaks at one hour. This DEVDase appears related to animal caspases at the biochemical level, being insensitive to broad-range cysteine protease inhibitors. In addition, caspase1, caspase-3 inhibitors and the pancaspase inhibitor p35 were able to suppress DNA fragmentation and cell death. These results suggest that UV radiation induce a PCD in plants that is apoptotic-like. This pathway appears however to have differences when compare to the animal pathway. In particular, there is no convincing evidence that plant cell activates PCD in response to DNA damage.