Negatives effects induced by exposure to ultra-violet (UV) radiation are well known. Nevertheless the modes of action of UV radiation are not well understood, in particular in soil invertebrates. In the present work, the effects of two UV doses (mimicking worst case scenarios in earth crust) on gene expression profile of Enchytraeus crypticus (Enchytraeidae, Oligochaeta) were investigated using the high-throughput 4 x 44K microarray developed for the species. Overall design: Gene expression profile of Enchytraeus crypticus was analysed after 5 days of exposure to UV radiation, in two different doses. To maximise UV exposure, the test media was reconstituted water (ISO 1). Three biological replicates per test treatment (two UV radiation doses) and control (standard laboratory light) were used.