Objectives: The aim of this study was to investigate the parameters of halitosis and sialometry in patients who had undergone head and neck radiotherapy, correlating oral concentration of volatile sulfur compounds (VSC) with the presence of tongue coating, salivary flow rate and BANA test. Material and Methods: 35 patients allocated in two groups were examined: group I (control) - patients with systemic and oral health; group II - patients submitted to head and neck radiotherapy. All volunteers were submitted to halitosis measurements through a sulphide monitor, evaluation of tongue coating weight, non-stimulated sialometry and BANA test. Results: The results were analyzed through analysis of variance, Pearson?s correlation and Student?s t-test, showing that there was statistically significant difference in halimetry between the groups, where the irradiated patients showed halitosis. There was a relation between the presence of tongue coating and the levels of VSCs in both groups and it was also noted that the irradiated patients showed a decreased salivary flow rate compared to healthy patients. Conclusion: On the conditions of the present research, it was concluded that halitosis can be considered an adverse effect of radiotherapy, connected to hiposalivation and poor oral health.