BACKGROUND: In intensive care units (ICUs), endotracheal tubes (ETTs) cause injury to the oral mucosa through friction and pressure. The incidence and risk factors of oral mucosal pressure injuries (PIs) have gained increasing attention in recent years. AIM: The study aimed to identify risk factors for oral mucosal PIs associated with ETTs. STUDY DESIGN: This was a single-centre brief follow-up longitudinal study conducted from January to May 2022. It recruited 250 patients without oral mucosal PIs who received mechanical ventilation support via ETT and were hospitalized in the ICU of a teaching and research hospital in Turkey. Receiver operating characteristic (ROC) analysis was performed to estimate the onset time of oral mucosal PI using the ETT repositioning time as an independent variable. RESULTS: Oral mucosal PIs associated with ETT developed in 41.6% of patients. Of the 250 endotracheally intubated patients, the mean Acute Physiology and Chronic Health Evaluation (APACHE-II) score was 27.5 (min/max: 18/42), the mean length of stay (LOS) in the ICU was 24 days (min/max: 13/80). The median body mass index (BMI) of patients with oral mucosal PIs was (24.59 [IQR = 3.81] kg/m CONCLUSIONS: Parenteral nutrition support and ETT repositioning timing were the primary risk factors for developing oral mucosal PIs. Close monitoring of endotracheally intubated patients receiving parenteral nutrition is essential, with particular attention to forming oral mucosal PIs. Additionally, repositioning the ETT at intervals of no more than 8 h may help reduce the risk of oral mucosal PI development. RELEVANCE TO CLINICAL PRACTICE: As ICU patients are particularly vulnerable to mucosal membrane PIs, recognizing the associated risk factors is crucial for early detection and prevention. This study highlights the specific risk factors for oral mucosal PIs, equipping nurses with the knowledge to develop targeted interventions to prevent these injuries.