A prospective study of two different respiratory culture techniques was performed in a group of hospitalized, ventilator-dependent children to compare costs and complications and to determine whether upper airway contamination of respiratory cultures could be reduced. Standard tracheal aspirate using a sterile suction catheter and Lukens trap was compared with cultures obtained using a blindly placed, protected double-lumen brush (PDLB). One hundred fifty-one PDLB specimens were obtained by blind passage of the sampling brush through the artificial airway. There were no complications with either technique. One hundred thirty-one tracheal aspirate and PDLB specimens met criteria for paired analysis. There was an average of 1.3 organisms isolated per PDLB specimen compared with an average of 3.1 organisms per tracheal aspirate. Sixty-five percent of the PDLB specimens were either sterile or contained only one organism. In comparison, only 13% of the tracheal aspirate cultures were sterile or had only one organism ( P < .0001). The mean cost of obtaining and analyzing PDLB specimens was $156 compared with a mean cost of $263 for tracheal aspirate samples. We conclude that in this population of ventilator-dependant children, blind, protected double-lumen catheter sampling of the lower airway for microorganisms is safe, rapid, and far less expensive, and yields specimens with lower numbers of potential bacterial pathogens than do traditional tracheal aspirates. The role of routine airway surveillance cultures in predicting or preventing nosocomial respiratory infection in ventilated patients remains to be clarified. However, if clinicians choose to perform such routine airway cultures we believe PDLB is the preferred method.