Background: This retrospective study investigated the incidence rate of accidental foreign body aspiration and ingestion according to patient sex, age, and dental department. This study aimed to verify whether the incidence rate is higher in geriatric than in younger patients and whether it is different among dental departments. Methods: Accidental foreign body aspiration and ingestion cases were collected from electronic health records and the safety report system of Yonsei University Dental Hospital from January 2011 to December 2017. The collected data included patients’ age, sex, medical conditions, treatment procedures, and foreign objects that were accidentally aspirated or ingested. The incidence rate was calculated as the number of accidental foreign body aspirations and ingestions relative to the total number of patient visits. Differences depending on the patients’ sex, age, and dental department were statistically identified. Results: There were 2 aspiration and 37 ingestion cases during the 7-year analysis period. The male to female incidence ratio was 2.8:1. The incidence rate increased with age and increased rapidly among those aged 80 years or older. Seven of the 37 patients with accidental foreign body ingestion had intellectual disability, Lou Gehrig’s disease, dystonia, or oral and maxillofacial cancer. The incidence rate was highest in the Predoctoral Student Clinic and the Department of Prosthodontics. The most frequently swallowed objects were fixed dental prostheses and dental implant components. Conclusion The incidence rate of accidental foreign body aspiration and ingestion differed according to patient sex, age, and dental department. Dental practitioners must identify high-risk patients and apply various methods to prevent accidental foreign body aspiration and ingestion in dental clinics. Inexperienced practitioners should be particularly careful.