The ruv operon of Escherichia coli consists of two genes, orf1 and ruv, which encode 22 and 37 kilodalton proteins, respectively, and are regulated by the SOS system. Although the distal gene, ruv, is known to be involved in DNA repair, the function of orf1 has not been studied. To examine whether orf1 is also involved in DNA repair, we constructed a strain with a deletion of the entire ruv operon. The strain was sensitive to UV even after introduction of low copy number plasmids carrying either orf1 or ruv, but UV resistance was restored by introduction of a plasmid carrying both orf1 and ruv. These results suggest that orf1 as well as ruv is involved in DNA repair. Therefore, orf1 and ruv should be renamed ruvA and ruvB, respectively.