Background: The ventilation bundle has been used in adult intensive care units to decrease harm and improve quality of care for mechanically ventilated patients. The ventilation bundle focuses on prevention of specific complications of mechanical ventilation; ventilator-associated pneumonia, sepsis, barotrauma, pulmonary oedema, pulmonary embolism, and acute respiratory distress syndrome. The Institute for Healthcare Improvement ventilation bundle consists of five structured evidence-based interventions: head of the bed elevation at 30e45 ; daily sedation interruptions and assessment of readiness to extubate; peptic ulcer prophylaxis; deep vein thrombosis prophylaxis; and daily oral care with chlorhexidine. Objectives: The objective of the study was to evaluate the use of the ventilation bundle in two intensive care units in Victoria, Australia. Methods: This is a 3-month prospective observational study in two intensive care units. Patient medical records were reviewed on days 3, 4, and 5 of mechanical ventilation using a prevalidated ventilation bundle checklist. Results: A total of 96 critically ill patients required mechanical ventilation for more than 2 d. Patients had a mean age of 64.50 y (standard deviation ¼ 14.89), with an Acute Physiology, Age, Chronic Health Evaluation (APACHE) III mean score of 79.27 (standard deviation ¼ 27.11). The mean ventilation bundle compliance rate was 88.3% on the three consecutive mechanical ventilation days (day 3 ¼ 79.4%, day 4 ¼ 91.1%, and day 5 ¼ 96.7%). There was a statistically significant difference in the mean APACHE III score between patients who had head of bed elevation and those without head of bed elevation, on days 3 (p ¼ <0.001) and 4 (p ¼ 0.007). Conclusion: The ventilation bundle elements were used in Australian intensive care units. The likelihood of having all ventilation bundle elements on day 3 was low if the patient's APACHE III score was high. However, the ventilation bundle compliance rate increased with mechanical ventilation days.