Background: This cross-sectional study investigated the factors influencing oral care in patients in intensive care units (ICUs) by identifying the current oral care practice status, perceptions, and attitudes of ICU nurses in Korea. Methods: This study surveyed 240 nurses with work experience in the ICU using a self-report questionnaire consisting of 22 items on the status, perception, and attitude towards oral care in the ICU. Results: A total of 227 questionnaires were analyzed. The average age of the participants was 29.79 ± 5.92 years, and the medical ICU was the most type of ICU. The factors affecting the attitude towards oral care and its importance in ICU patients were the experience of working as a nurse (r = 0.336, p < 0.01), ICU work experience (r = 0.218, p < 0.01), and oral care practice frequency (r = 0.167 p < 0.05); these were found to be statistically significant. Conclusions: In this study, the interest of the nurses in oral care practice and education was high, but professional education and the regular implementation of oral care practices were insufficient. To address these problems, it will be necessary to improve oral care practices through dental intervention and education about oral care methods focused on ICU patients.