A key component of iron metabolism is the storage of Fe(III) in bacterioferritin and its subsequent mobilization as Fe(II) to satisfy metabolic requirements. In P. aeruginosa, the mobilization of Fe(III) from bacterioferritin (Pa Bfr) to the cytosol requires binding of a ferredoxin (Bfd) to reduce the stored Fe(III) and mobilize it as the soluble Fe(II). This presentation will discuss evidence showing that deletion of the bfd gene from the P. aeruginosa genome triggers an irreversible accumulation of Fe(III) in Pa Bfr, concomitant intracellular iron deficiency, metabolic dysregulation, and impaired biofilm development. Small molecule inhibitors designed to bind Pa Bfr at the Bfd binding site penetrate the P. aeruginosa cell and kill biofilm-entrenched cells. A structural alignment of Pa Bfr and Acinetobacter baumannii Bfr (Ab Bfr) showed strong conservation of the Bfd binding site on Ab Bfr. Accordingly, the small molecule inhibitors of the Pa Bfr-Bfd complex accumulate in the A. baumannii cells, elicit an iron starvation response, are bactericidal to planktonic cells and exhibit synergy with existing antibiotics. These observations suggest that the inhibition of iron mobilization from bacterioferritin may be a new antimicrobial strategy applicable to other Gram-negative pathogens