Objectives: The purpose of the study was to find out dental caries and periodontal disease based on oral healthcare of adults in Busan. This study will provide the preventive oral healthcare for the periodontal diseases and dental caries. Methods: The study subjects were 369 people from the regular dental health checkup in the general hospital in Busan. After receiving informed consent, a self-reported questionnaire was completed from October 1, 2014 to January 31, 2015. The questionnaire consisted of dental caries and periodontal diseases by direct examination and tooth brushing method. Data were analyzed by 2 test, Fisher``s exact test, and Pearson``s correlation. Results: In the morbidity of dental caries and periodontal diseases, the dental caries was most common in those having restored teeth(236 subjects, 64%), while periodontal diseases were found in mild cases of gingival inflammation in 285 subjects(77.2%), and mild cases of dental calculus in 274 subjects(73.4%). Most of the respondents replied that they did not have systemic disease or oral health related symptoms. According to tooth brushing pattern, dental caries experiences were most common in those having less frequent tooth brushing less than 3 minutes and no tongue brushing. The outbreak of dental caries was more common in 5 times than 3 to 4 times a day. Conclusions: The education of the right tooth brushing method and use of dental floss is the most important prevention of dental caries and periodontal disease in the adults.