The objective was to assess the relationship between number of functional occluding natural pairs of teeth and health related functioning in older free living Japanese people using the SF-20. The participants were 107 elderly people aged 80 years. Health related functioning was measured with the SF-20. The numbers of functional occluding natural pairs of teeth (OPs) were calculated and scored as follows: 1, for each pair of anterior teeth and premolars in occlusion. Molar functional natural occluding pairs were scored 2 for each occluding pair. The number of functional occluding pairs was assessed separately as anterior natural occluding pairs (AOPs) and posterior occluding pairs (POPs). There were significant differences in the role functioning subscale of SF-20 between those who were edentulous and those with one to nine natural teeth and 10 or more natural teeth (P = 0.030). Those with one to six AOPs had significantly higher role functioning than the zero AOPs group (P = 0.042). Those with 1-12 POPs also had significantly higher role functioning scores than the zero natural POPs group (P = 0.007). However, there were no significant relationships between number of natural teeth, OPs or AOPs, and POPs on the one hand, and all other subscales of SF-20 on the other hand. The community-dwelling 80-year-old Japanese people in this study had overall good health related functioning. The number of functional occluding pairs of natural teeth, especially POPs, was related with the role functioning subscale of SF-20 but had no significant relationships to the other dimensions of SF-20.