OBJECTIVE This study investigated intensive care unit nurses' knowledge, attitudes and practices of oral care for intubated patients together with the associated factors of the same. BACKGROUND Effective oral care improves patient comfort and prevents oral infection. Although oral care is a common requirement of nursing practice, providing intubated patients with oral care is a challenging task. METHODS A descriptive, cross-sectional design. METHODS This study applied purposive sampling method at 12 adult intensive care units in one medical centre in northern Taiwan. Two hundred and five nurses were recruited. Data were collected by structured questionnaires which consisted of four sections: knowledge, attitudes and practices of oral care for intubated patients and demographic information for the nurses. RESULTS The average percentages indicating the intensive care unit nurses' oral care knowledge, attitudes and practices were 58·8, 79·4 and 49·8%, respectively. Higher scores on oral care knowledge were associated with nurses performing oral care more frequently. Nurses learning about oral care from reading related studies and materials of their own accord may increase the frequency with which they provide oral care to intubated patients. The nurses' age and the type of intensive care unit they work in were significant factors related to the frequency of performing practices related to oral care. CONCLUSIONS Findings show that nurses who have more resources for learning about oral care have greater knowledge about it and provide oral care to intubated patients more frequently. CONCLUSIONS Encouraging nurses to learn more about oral care using diverse educational resources will enhance their knowledge and improve their practice. Nursing administrators are encouraged to establish policies and procedures for oral care of intubated patients based on the type of patients cared for, in addition to holding in-service training, with a view to enhancing the quality of oral care for critically ill patients.