Objective To explore the type and frequency of oral care practice in intensive care units (ICUs) in Mainland China, and to provide evidence and suggestions for improving oral care practice. Methods Three survey methods, including mailing questionnaires to ICUs of Grade 3A hospitals, consulting experts in this field and visiting accessible ICUs, were used to survey current oral care practice in Mainland China. Results A total of 184 questionnaires were given to the subjects, of which 79 effective ones were collected, and the response rate was 42.93%. All 79 respondents considered oral care very unimportant, and 98.7% of the ICUs performed oral care in different ways. Currently, the cotton ball wipe-off method was the most frequently used for oral care (62.5%), with an average (9.1± 5.1) min per time, twice or three times daily. The mouthwashes often used were saline (76.1%), solutions containing sodium bicarbonate (22.8%), furacilin (13.9%), and hydrogen dioxide (13.9%). Conclusion The oral care practice for the critically-ill patients in ICUs of China is unsatisfactory, although it is perceived as an important item in nursing care. More evidence–based training should be given and it is necessary to establish a national oral care guideline for critically-ill patients.