Ventilator-associated pneumonia (VAP), nosocomial pneumonia occurring more than 48 hours after ventilator use, is a common complication of mechanical ventilation with high mortality. The use of VAP can make it difficult for patients to wean themselves from the ventilator, lengthen hospital stays, and place a significant financial burden on the patient and a significant need for medical resources. Ventilators are an effective life-saving intervention for critically ill patients and are commonly used in intensive care units (ICUs). Ventilator-associated pneumonia (VAP) is a form of nosocomial infection that occurs after more than 48 hours of ventilator use. The 2016 clinical guidelines published by the Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) reported that his mortality from VAP in the United States reached 13% of his age. Ventilator-associated pneumonia (VAP) is a form of hospital-acquired pneumonia (HAP) that develops after more than 48 hours of ventilator use. VAP is a common and serious problem in the ICU and is associated with an increased risk of death. Accurate diagnosis is critical to allow early initiation of appropriate treatment while avoiding antibiotic overuse and subsequent antibiotic resistance. Her HAP patient with severe requiring mechanical ventilation after the onset of infection does not meet the definition of VAP. This is called ventilated nosocomial pneumonia (VHAP). However, the microbiology, diagnostic evaluation, and outcome of VHAP are more similar to VAP than to HAP. Here, we review the clinical presentation and diagnosis of VAP. The epidemiology, etiology, risk factors, and prevention and treatment of VAP are discussed separately. Ventilator-associated pneumonia (VAP) remains the most common infectious complication in patients admitted to the intensive care unit (ICU). This results in higher morbidity and mortality, longer treatment times, and higher hospital costs. The incidence of VAP varies widely between studies, depending on the diagnostic criteria used, ICU type, and patient population. Furthermore, the causative organisms vary by ICU patient demographics, hospital/ICU length of stay, and institutional antimicrobial policies. Ventilator-associated pneumonia (VAP) was defined by the Centers for Disease Control (CDC) as pneumonia occurring in a patient who had been intubated and mechanically ventilated on the day of the event for more than 2 calendar days. A clinical diagnosis of pneumonia was defined as the presence of new or progressive lung infiltrates or consolidation or cavitation on chest radiograph associated with at least 2 of the following criteria: Body temperature >38°C or <36>12000/mm3 and changes in the characteristics of purulent tracheal secretions or pre-existing secretions. Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) significantly increase hospital morbidity and mortality. Rapid diagnosis is especially difficult in intensive care units. This is because a variety of other causes can contribute to clinical deterioration in complex and critically ill patients. The authors describe the diagnosis, treatment, and prevention of these diseases based on current guidelines and recent knowledge. Ventilation-associated pneumonia (VAP) causes significant morbidity and mortality in the intensive care unit (ICU). Ventilator-associated pneumonia is defined as pneumonia that occurs more than 48 hours after intubation and initiation of mechanical ventilation. Intubated patients are at increased risk of pneumonia due to impaired mucociliary clearance caused by endotracheal tubes. Ventilator-associated pneumonia (VAP) occurs in her 9–27% of her ICU patients requiring a ventilator. To meet VAP criteria, pneumonia must be present for at least 48 hours after intubation.