Objectives: To date, no nationally-representative epidemiological survey of xerostomia has been undertaken. The aim of this study was to examine the prevalence, associations and impacts of xerostomia in a nationally representative sample of dentate adult community dwelling New Zealanders aged 18 years and above. Methods: The data were collected as part of the 2009 New Zealand Oral health Survey (NZOHS). A representative sample of 3475 adults (representing approximately 94% of the population) participated in this snapshot survey of community-dwelling New Zealanders. The sample comprised 1267 Māori, 353 Pacific Islanders, 518 Asian and 2125 European/other people. There were 2209 dentate adults in the sample. Data were collected using face-to-face interviews and dental examinations. The OHIP-14 was used to investigate xerostomia's impact on oral-health-related quality of life. The Stata 12 statistical package was used for all analyses. Data analysis took the complex survey design into account by using appropriate weighting for all procedures. Univariate and bivariate analyses were undertaken to describe the sample and the unadjusted associations. Multivariate modeling (logistic and binomial regression) was used to examine the association between xerostomia, sociodemographic characteristics and oral health impacts.Results: The overall prevalence estimate for xerostomia was 13.1% (approximately one in eight). There was a gender difference, with more xerostomic females than males. Individuals aged 75+ and those between 25 and 34 years old had the highest odds (OR 6.5 and OR 4.0 respectively) of experiencing xerostomia. Xerostomia was strongly associated with the mean OHIP-14 score (after controlling for covariates such as sociodemographic characteristics and oral health indicators), but xerostomics were not more likely to experience one or more oral health impacts. Xerostomic individuals had a higher mean OHIP score and a higher prevalence of oral health impacts than non-xerostomic individuals. Xerostomia was also strongly associated with being female, Pacific Islander or Māori, and with having periodontitis. The oral-health-related quality of life domains most strongly associated with xerostomia were functional limitation, handicap and social disability; those with the weakest association with it were physical pain and psychological discomfort.Conclusion: Xerostomia is a distressing condition which affects New Zealanders of all ages, particularly those older than 45 and those aged between 25 and 34 years. In addition, females, Māori and Pacific Islanders and individuals with periodontitis are most likely to suffer. Moreover, xerostomia affects complainants' day-to-day lives by limiting oral function and impinging on their psychosocial well-being. These findings suggest that xerostomia is a chronic condition of some consequence to the individual sufferer. Xerostomia in dentate New Zealand adults constitutes an important public health issue.