Background: Oncological therapy can trigger various complications and side effects in certain tissues, such as the oral cavity, inducing a direct or indirect impact on basic functions and the patient's quality of life. The aim of the study is to determine the prevalence of chronic oral complications of oncological treatments in patients with head and neck cancer and assess their possible relationship with risk indicators associated with the patient, the tumor, and the treatment., Material and Methods: A retrospective, single-center, observational pilot cohort study was designed at the Dental Hospital of the University of Barcelona, involving patients with head and neck cancer who underwent surgery, non-surgical oncological therapy (radiotherapy/chemotherapy/immunotherapy), or combined therapy. Medical histories were analyzed, and data related to demographics, toxic, hygienic, and dietary habits, systemic and oral health status, characteristics of cancer and its treatment, and registered chronic oral complications were collected. The results were expressed in descriptive measures (means, standard deviations, counts, prevalence, and 95% confidence intervals), and for statistical associations, parametric and non-parametric tests were used., Results: The overall prevalence of chronic oral complications was 92.57%. Dental disease (81.14%), periodontal disease (65.14%), and hyposalivation/xerostomia (62.86%) showed the highest prevalence. Advanced age, certain cancer locations, advanced cancer stages, and oncological therapy including radiotherapy were significantly associated with the presence and number of complications., Conclusions: The elevated noticed prevalence necessitates rigorous monitoring and preventive care. The combination of risk factors can significantly contribute to oral complications. Understanding these factors services dentists establish protocols for preventing, diagnosing, and treating oncology patients.