Purpose: Obstructive sleep apnea syndrome (OSAS) is a sleep disorder characterized by repetitive episodes of upper airway obstruction. Recently, it has been suggested that edentulism worsens sleep apnea; sleeping without dentures is associated with a significant increase in the apnea-hypopnea index. OSAS is also related to depression. The aim of this study was to assess, in a group of elderly occupants in residential homes in the Turin district of Italy, (1) the prevalence of key symptoms and indicators of OSAS and the prevalence of depressive feelings; (2) how the reduction of vertical dimension of occlusion (VDO) influenced the onset of OSAS; and (3) whether a relationship between OSAS and depression was present. Materials and Methods: The sample population consisted of 403 people (77% men, 23% women; age range, 65 to 90 years). The subjects underwent the Italian version of the Mini Mental State Examination (MMSE) to assess their mental condition. The remaining collaborating subjects completed 2 questionnaires to assess the risk of OSAS (Berlin Questionnaire) and depressive feelings (Beck Depression Inventory). Results: Of the 403 elderly residents initially evaluated with the MMSE, 97 were excluded from the study, reducing the sample size to 306 subjects (75% women, 25% men; mean age ± standard deviation, 83.12 ± 11.10 years).The analysis of these data revealed a statistically significant association between the risk for sleep apnea and the VDO (P < .0001), and between sleep apnea and depressive feelings (P < .05). Conclusion: This study revealed that inadequate VDO is closely associated with the risk of OSAS, and that depressive feelings are more present if there is a high risk for OSAS. Int J Prosthodont 2005;18:316–322.