The aim of the present study was to determine the relationship between tracheotomy and ventilator-associated pneumonia (VAP). The study used a retrospective case-control study design based on prospective data. All nontrauma immunocompetent patients, intubated and ventilated for >7 days, were eligible for inclusion in the study. A diagnosis of VAP was based on clinical, radiographical and microbiological criteria. Four matching criteria were used, including duration of mechanical ventilation (MV). The indication and timing of tracheotomy were at the discretion of attending physicians. Univariate and multivariate analyses were performed to determine risk factors for VAP in cases (patients with tracheotomy) and controls (patients without tracheotomy). In total, 1,402 patients were eligible for inclusion. Surgical tracheotomy was performed in 226 (16%) patients and matching was successful for 177 (78%). The rate of VAP (22 versus 14 VAP episodes.1,000 MV-days(-1)) was significantly higher in controls than in cases. The rate of VAP after tracheotomy in cases, or after the corresponding day of MV in controls, was also significantly higher in control than in case patients (9.2 versus 4.8 VAP episodes.1,000 MV-days(-1)). In multivariate analysis, neurological failure (odds ratio (95% confidence interval) 2.7 (1.3-5)), antibiotic treatment (2.1 (1.1-3.2)) and tracheotomy (0.18 (0.1-0.3)) were associated with VAP. In summary, the present study demonstrates that tracheotomy is independently associated with decreased risk for ventilator-associated pneumonia.