Background and Purpose To investigate the association between the mean salivary gland and oral cavity dose, with patient-rated moderate and severe xerostomia and sticky saliva. Patients and methods One hundred and fifty-seven patients treated with bilateral irradiation for head and neck cancer were included. The parotid and submandibular glands and the oral cavity were delineated on plannings-CT scans. At baseline and 6 and 12 months self-reported xerostomia and sticky saliva were assessed using the EORTC QLQ-H&N35 questionnaire. Results At 6 months a significant association between the mean parotid (MD par) and mean submandibular dose (MD subm) and xerostomia was observed (OR−MD par: 1.17; P=0.002 and OR−MD subm: 1.08; P=0.02). Between MD par and MD subm, a significant interaction term was present. No significant association was found with the oral cavity dose. Xerostomia was reversible depending on MD par and MD subm. Considering Sticky saliva, a significant association was found at 6 and 12 months with MD subm (OR: 1.03; P<0.001). The P50 for sticky saliva increased with elapsing time. Conclusions Both MD par and MD subm influence the risk of xerostomia in irradiated patients at 6 months. This probability as a function of the mean parotid dose significantly depended on the mean dose in the submandibular glands. Sticky saliva mainly depends on MD subm.