Objective: Evaluate the relation of nursing workload, evaluated by the Nursing Activities Score (NAS), with the occurrence of Ventilator-associated Pneumonia (VAP) in an Intensive Care Unit (ICU) and the impact of VAP on hospitalization costs.Methods: Retrospective cohort study in Adult ICU of a high complexity Brazilian university hospital. The profile, outcomes, costs, and daily NAS from patients were collected. We also proposed some workload indicators based on NAS daily evaluation.Results: The study included 195 patients, 27.17% diagnosed with VAP. VAP was more prevalent in patients diagnosed with trauma on admission. The total costs of care were higher for VAP patients. In all multivariate models tested were predictive for VAP: the patient's intubation that occurs in days prior of the ICU admission day (higher risk if occurs in days prior the ICU admission day) and ventilation time prior ICU (higher risk if higher time). We found others predictors, but these were dependent on the model tested. Additional risk predictors were tracheostomy, propofol use, neuromuscular blocker use and the higher NAS from admission. The protective factors found were the percentage of adequacy of the assignment based in NAS that measure if the workload measured by the NAS was offered and the increment in NAS during the ventilation time.Conclusions: The offering of an adequate nursing work scale (adequate number of professionals for the care), as a function of the nursing workload measured by the NAS, could be effective in the reduction of VAP, hospital stay time and hospital costs.