Magnetic particles have been studied with much interest with reference to many engineering applications. Much effort has been devoted to the preparation of nano-sized magnetite particles with well-controlled size and shape. Magnetic bacteria synthesize uniform and nano-sized magnetite particles enveloped by organic lipid membranes. This review discusses recent advances in bacterial magnetite particles. Especially, the tremendous biotechnological potential of bacterial magnetite particles (BMPs) and our recent understanding of mechanism of magnetite particle formation in Magnetospirillum magneticum strain AMB-1 were highlighted.