Background: Bisphosphonate-associated osteonecrosis of the jaws (BAONJ) is a complication of great medical importance. Some of the most discussed and controversial aspects are the risk factors, some of which are related to patients' smoking and alcohol consumption. The Aim: To study cancer patients with BAONJ and determine their participation in the mentioned above risky health-related habits. Material and methods: A prospective epidemiological study of 112 patients diagnosed with bisphosphonate-associated osteonecrosis of the jaw in 2016 and 2017 was conducted at the Clinic of Maxillofacial surgery of University hospital "St. George", Plovdiv, Bulgaria, based on anamnesis, clinical examination, and hospital documentation. SPSS Statistics v.24 was used for statistical analysis, at a significance level p<0.05. Results: Over 2/3 of the patients were smokers (40.18%) or ex-smokers (25.00%), which linked them with the risk factor of smoking. At the time of the study, patients smoking between 1 and 9 and between 10 and 19 cigarettes a day had equal relative shares of 44.22%. More than half of the patients smoked from the age of 20-39, which we explain by the high average age. The majority of patients studied consumed alcohol, most often once a week or on weekends (28.57%) or only on occasions (26.79%), followed by 24.11% who used alcohol several times per week. Nearly 2/3 drink drinks with both low and high alcohol content. Conclusion: The highest proportion of patients are smokers / ex-smokers and consume alcoholic beverages occasionally, which links them to these risk potential factors.