Resumo BACKGROUND: The few existing studies on herpes labialis among health care workers have been predominantly among non-dental health care workers. The purpose of this study was to determine Nigerian dental health care providers' knowledge of, attitudes toward, preventive behaviors for, and refusal to treat patients with herpes labialis. METHODS: This cross-sectional study was conducted among final-year dental students at the University of Benin, dental house officers, and residents at the University of Benin Teaching Hospital, Benin City, Nigeria. Data collection was via a self-administered questionnaire. Bivariate statistics and logistic regression were used to relate the dependent and independent variables. RESULTS: Of the 120 questionnaires distributed, 110 were completed and returned, giving a 91.7% retrieval rate. However, 15 of the returned questionnaires were discarded because they were improperly completed, leaving a total of 95 questionnaires for final analysis in this study. The majority of participants were over 28 years old (54.7%), male (67.4%), unmarried (66.3%), and postgraduate dental health care providers (51.6%). Less than half (43.2%) of participants demonstrated adequate overall knowledge of herpes labialis. About one-tenth (10.5%) and more than three-quarters (87.4%) of participants reported a positive attitude and performance of adequate preventive behaviors, respectively. A total of 16.8% of participants reported a high tendency to refuse treatment to patients with herpes labialis. Although not statistically significant, young, unmarried, male undergraduate participants reported a greater likelihood to refuse treatment to herpes labialis patients. We found a statistically significant positive correlation between attitude and refusal to treat patients with herpes labialis. However, marital status and the attitude of participants toward these patients emerged as the determinants for refusal to treat patients with herpes labialis. CONCLUSIONS: Data from this study revealed a high level of inadequate knowledge, negative attitudes, and reasonably adequate preventive behaviors with respect to herpes labialis. One out of every six dental health care workers studied reported having refused to treat patients with herpes labialis. Unmarried dental health care providers and those with negative attitudes toward herpes labialis patients were more prone to refuse treatment to these patients.