Introduction: Prader-Willi Syndrome (PWS) is a genetic disorder caused by the lack of expression of certain paternal genes located on chromosome 15q11-q13. This anomaly causes cognitive, neurological and endocrine abnormalities, among which one of the most important is hyperphagia. The aim of this study was to assess the oral health of children with PWA and to establish preventive criteria. Results: Thirty patients with PWS (mean age 10.2 years) and 30 age-and gender-matched controls were included in the study. Twenty-six patients with PWS(86.6%) followed dietary treatment prescribed by their endocrinologist. Individuals with PWS had a mean caries index of 53.3% and Decayed Missing Filled teeth (DMFT) index 2.5, and 53.3% had gingivitis, in the control group the respective figures were 43.3%, 0.93, and 60%. Only the DMFT index (p 0.017) presented significant differences. Regarding stimulated salivary secretion, patients with PWS presented a mean of 0.475 ml/min with a pH of 6.15, while controls presented a mean of 0.848 ml/min with a pH of 7.53; the differences between the groups were statistically significant in both cases (p 0.032 and p 0.0001 respectively). The population with PWS presented a higher plaque index (> 2) than their healthy peers, but the differences were not significant. Conclusion: Pediatric patients with Prader-Willi syndrome have an increased risk of caries and gingivitis. The children with this syndrome have a decreased salivary flow and a more acidic salivary pH. In these patients, dental care is an essential part of their multidisciplinary medical treatment.