Immunolocalizations of calbindin D-28k (CB) and osteonectin (ON) in human carious teeth were studied by using an indirect immunofluorescence method. Carious teeth were decalcified and cryostat sections were prepared for immunofluorescence staining. Sections were incubated with anti-CB antibody and anti-ON antibody, followed by the incubation with tetramethyl rhodamine-conjugated swine anti-rabbit IgG and FITC-conjugated donkey anti-mouse IgG. They were examined under a confocal laser scanning microscope. The sections were then stained with hematoxylin-eosin. In hematoxylin-eosin stain, tertiary dentin with the tubule-poor pattern was observed underneath carious lesion, and this dentin was eosinophilic. Beneath this dentin, odontoblasts usually lacked CB immunoreactivity, whereas ones underneath the secondary dentin in carious teeth showed the immunoreactivity. ON immunoreactivity was detected in odontoblasts and dentin in carious teeth. Odontoblasts beneath the tertiary dentin, however, showed the weak ON immunoreactivity regardless of the moderate immunoreactivity in odontoblasts underneath the secondary dentin. The tertiary dentin also showed the thin ON immunoreactivity regardless of the moderate immunoreactivity in primary and secondary dentin. In conclusion, it was demonstrated that the expressions of CB and ON immunoreactivities in odontoblasts and dentin underneath carious lesion were different from those underneath the portion without carious lesion in carious teeth. These findings may suggest that the odontoblasts underneath carious lesion became inactively after the formation of tertiary dentin.