Xerostomia is commonly measured and graded using objective measures of major salivary gland output and observer-rated toxicity grading. The separation between the different grades is somewhat ambiguous in the current toxicity grading systems. We propose a new grading system based primarily on the functional deficits associated with xerostomia. Salivary flow rates have been added as a criterion to the grading system, notwithstanding the weak correlation reported in most studies between the symptoms and objective functional measures. In addition to the observer-rated toxicity grading, recording of patient-reported quality of life, using validated instruments, is encouraged.