Brucellae are facultative intracellular bacterial pathogens of a zoonotic disease called brucellosis,a zoonotic disease affecting humans and animals worldwide.The mechanism how Brucella species cause disease is not well known.Here we investigated small size RNA fragments of Brucella melitensis,predicted and confirmed milRNA existence by high throughput sequencing and northern blot.Bacterialribonuclease Ⅲ (RNase Ⅲ) is a highly conserved endonuclease,whichplays pivotal roles in RNA maturation and decay pathways by cleaving double-stranded structure of RNAs.