Pasteurella multocida is the causative agent of a number of economically important diseases, including avian fowl cholera. Numerous P. multocida virulence factors have been identified, including capsule, lipopolysaccharide (LPS) and filamentous hemagglutinin, but little is known about how their expression is regulated. Hfq is an RNA-binding chaperone protein that facilitates riboregulation via interaction with small noncoding RNA molecules (sRNAs) and their mRNA targets. To investigate the role of Hfq and sRNAs in P. multocida gene regulation, an hfq mutant was constructed in P. multocida strain VP161. The hfq mutant produced significantly less hyaluronic acid capsule during all growth phases, was attenuated for virulence in chickens and displayed reduced in vivo fitness in mice. Transcriptional and proteomic analyses of the hfq mutant showed that 128 genes and 78 proteins were differentially expressed at mid-exponential growth phase and 106 proteins were produced at altered levels during early-exponential growth phase. Both the RNA transcript and protein levels for genes/proteins involved in capsule biosynthesis were reduced in the hfq mutant, as were the levels of the filamentous hemagglutinin protein PfhB2 and its secretion partner LspB2. In contrast, expression of phosphocholine and phosphoethanolamine transferase genes, involved in LPS biosynthesis, was increased, suggesting that these genes are negatively regulated by Hfq-dependent mechanisms. Additionally, PlpB, a lipoprotein involved in P. multocida virulence, displayed increased transcript and protein levels. These data show that Hfq plays a crucial role in the regulation of the key P. multocida virulence factors, capsule, LPS, filamentous hemagglutinin and PlpB.