This chapter discusses data collection and audit, where data collection is an essential aspect of management of patients with head and neck cancer. The evidence base for management of head and neck tumors is low with relatively few randomized controlled trials. One of the main contributing factors for the poor evidence is the lack of prospective and accurate data collection and audit in units treating head and neck cancer. Accurate record-keeping and documentation allows for proper audit of results and comparisons of outcome by ensuring that like is compared with like. Comorbidity has been shown to be a determinant in treatment selection and survival in various cancers. With respect to chemotherapy the following complications should be recorded, such as leucopenia, thrombocytopenia, infections, nausea and vomiting, severe mucositis, neurotoxiciy, diarrhea, renal failure and alopecia. Audit is defined as the systematic appraisal of the implementation and outcome of any process in the context of prescribed targets and standards.