In 15 elderly residents of an old-age home, we measured the total number of bacteria and the numbers of streptococci and staphylococci in the pharynx over 5 months. Seven residents received professional oral health care from dentists and dental hygienists and eight practiced oral care by themselves or together with a helper. During the 5 months, the total number of bacteria and the numbers of streptococci and staphylococci decreased (p < 0.01) in those who received professional care. In contrast, the total number of bacteria and the numbers of streptococci and staphylococci neither did not change or increased in those who did not receive professional care. These findings show that professional oral health care by dentists and dental hygienists can decrease the total number of bacteria and the numbers of streptococci and staphylococci in the pharynx of elderly people, which might prevent aspiration pneumonia.