Aims: To investigate the formation of fructosyltransferase (FTF) complexes on hydroxyapatite (HA) surfaces. Methods and Results: Cell-free extracellular FTF from Streptococcus mutans, purified from hyperproducing strain V-1995, was adsorbed onto HA and then eluted from the surface by means of a concentration gradient of potassium phosphate buffer. The FTF monomers loaded onto HA formed, upon adsorption, various complexes ranging from 200 to 700 kDa as demonstrated using native PAGE. All these complexes exhibited enzymatic activity. Conclusions: Adsorption of FTF onto HA induced the formation of stable and enzymatically-active complexes. Significance and Impact of the Study: The formation of these complexes may explain the change of FTF catalytic properties after adsorption onto HA. This study is another step in determining the properties of a-cellular constituents of the oral biofilm.