Institutionalised elderly often report oral and dental problems which reduce nutrition ability and compromise significantly quality of life. The main objective of this study was to assess the prevalence of oral diseases in a group of residential homes elderly and to evaluate the association between degree of edentulism and some individual characteristics. From November 2004 to April 2005 448 subjects living in 10 residential homes of the city of Rome were enrolled in a special dental health programme in Lazio (Central Italy). The median age was 83.2 yrs, 47.3% of the subjects were edentulous, while 24.8% had 1 to 9 teeth, 63.1% of whom didn't have denture. 57.1% of subjects reported one or more oral disorders. Multivariate analysis showed a significant association between edentulism and the following factors: age > or = 75 yrs (Odds Ratio [OR] = 3.16 CI 95% 2.11-4.74) permanence of stay in the residential home > or = 3 yrs (OR = 1.96 CI 95% 1.13-3.40), lack of routine dental visits (OR = 1.71 CI 95% 1.14-2.58). The study findings confirmed that institutionalised elderly subjects, together with several chronic diseases, also show a poor oral health. Consequently greater attention should be paid to improve actively oral health services in this care setting.