Nanobacteria (NB) are the smallest known cell-walled self-replicating described bacteria to date; with dimensions of 20-200 nm isolated from human and cow blood. They are originally discovered by two researchers from Finland & Turkey, Drs. E. Olavi Kajander and Neva Ciftcioglu working at the University of Kuopio in Finland. NB are efficient nuclei of mineralization that start the formation of apatite from soluble calcium and phosphorus compounds at physiologic concentrations and conditions. So these microorganisms are believed to be etiological agents of pathological extra skeletal calcification.We pointed out the paradoxical role of fetuin (an anti-mineralization protein) in the formation of these self-propagating mineral complexes which we propose to call Ânanons.Â Phylogenetic analysis based on comparison of 16S ribosomal DNA sequences has placed the NB isolated from fetal calf serum into the á-2 subgroup of Proteobacteria. This review elucidates the chemical & biological structure of NB through isolation, identification & molecular characterization of NB species from different animals & human sources.Moreover, to explain themethods to diagnose NB in biologics, cells, tissues, blood, and urine with immuno-detection with NB-specific monoclonal antibodies, electron microscopy, and coculture techniques.