Rho-independent termination is a major mechanism of transcriptional arrest in bacteria that controls both normal 3' termination and a wide array of regulatory attenuation events. Detecting Rho-independent terminators is an obliged step in the annotation of bacterial operons. Yet, while several efficient algorithms are available for this purpose, there is no freely available web site enabling a rapid scanning of raw genomic sequence for the presence of terminators. Here we implemented such a web server, which combines two published prediction algorithms, Erpin and RNAmotif, and performs nearly as well as more complex procedures while being accessible to the non specialist. The ARNold Web server is available at : http://rna.igmors.u-psud.fr/toolbox/arnold/