Background: Evidence from observational studies have raised the possibility that statin treatment re duces the incidence of certain bacterial infections, particularly pneumonia. We analyzed data from a randomized controlled trial of rosuvastatin to examine this hypothesis. Methods: We analyzed data from the randomized, double-blind, placebo-controlled JUPITER trial (Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin). In this trial, 17 802 healthy participants (men 50 years and older and women 60 and older) with a low-density lipoprotein (LDL) cholesterol level below 130mg/dL (3.4mmol/L) and a high-sensitivity C-reactive protein level of 2.0mg/L or greater were randomly assigned to receive either rosuvastatin or placebo. We evaluated the incidence of pneumonia on an intention- to-treat basis by reviewing reports of adverse events from the study investigators, who were unaware of the treatment assignments. Results: Among 17 802 trial participants followed for a median of 1.9 years, incident pneumonia was reported as an adverse event in 214 participants in the rosuvastatin group and 257 in the placebo group (hazard ratio [HR] 0.83, 95% confidence interval [CI] 0.69-1.00). In analyses restricted to events occurring before a cardiovascular event, pneumonia occurred in 203 participants given rosuvastatin and 250 given placebo (HR 0.81, 95% CI 0.67-0.97). Inclusion of recurrent pneumonia events did not modify this effect (HR 0.81, 95% CI 0.67-0.98), nor did adjustment for age, sex, smoking, metabolic syndrome, lipid levels and C-reactive protein level. Interpretation: Data from this randomized controlled trial support the hypothesis that statin treatment may modestly reduce the incidence of pneumonia.