In the retrospective case-control study, diagnostic criteria have been established for controlled ventilation (CV)-related pneumonias in newborn infants. Kept under medical surveillance were 50 neonates having been treated at the Lvov Regional Hospital intensive therapy unit all the year in 2000. All babies were exposed to more than 24-hr CV; they had no symptoms of infectious diseases during the first 48 hours of life. The main group was 15 decreased infants with autopsy-verified diagnosis of nosocomial pneumonia, the control group being 35 pneumonia-free babies. There was no significant difference in prevalence of perinatal risk factors and primary lung pathology patterns between the groups, the low-birth-weight- and shorter-gestational age infants having developed post-ventilation pneumonia more frequently. But all such signs tended to lose their significance with logistic regression analysis. It is the baby's grave general condition (reflected by scores on the Neonate Acute Physiology Scale > 16), changes in organoleptic properties of the tracheal aspirate, hemoptysis, an excessive oxygenation index (> 0.07), earlier development of anemia (Ht < 35%), radiographic lung infiltrates that can be considered to be significant diagnostic criteria for CV-associated pneumonias after 100-hr CV. Sensitivity of the complex of the criteria proposed is 78.57%, specificity--96.67%, prognosis of the positive result is accurate up to 91.67%, prognosis of the negative result is accurate up to 90.63%.