Patients affected by Prader-Willi Syndrome (PWS) usually show orofacial dysfunction, poor oral hygiene, severe tooth wear, generalized caries and thick sticky saliva. The aim of this study was to evaluate molecular/ionic changings in PWS patients compared to controls, as well as unstimulated salivary flow rate (SFR); 7 patients with a mean age of 20.0±5.45 years were enrolled in the study group (PWS group) and 5 patients with a mean age of 22.6±3.05 years, in the control group. Results showed a greater Na+ (p=0.003), Cl+ (p=0.004) and P (p=0.001) concentration in saliva of PWS group as well as a greater concentration of secretory IgA (p=0.003) with a reduction of SFR (p=0.004) compared to controls. A Spearmans analysis (based on the SFR of both groups) revealed an inverse correlation with Na (rho=-0.747), Cl (rho=-0.723), P (rho=-0.637) and sIgA (rho=-0.707) concentration and SFR, when linear regression model was performed only P and SFR were interdependent (ß=-0.748; p=0.005).