This observation study examined the behaviors of 20 sedated, mechanically ventilated children, ages 1 month to 14 years. Observations were made using the Comfort Scale at the beginning and end of the two-hour observation period and of body and facial movements, behavior state, and environmental activity occurring during the 2-hour period. Mean Comfort scores at both measurement points were 16, below the target sedation level. In addition, while most children were in sleep states, they exhibited many body movements, particularly of the upper extremities. Body movements were related to behavior state but not to Comfort scores. Environmental activity was not significantly related to child activity, behavior state, or Comfort scores. Sedation scales in children may be best used in conjunction with behavior observations although further research is needed to determine the predictive capabilities of either scales or behavior on actual ventilation outcomes., Mechanical ventilation has contributed substantially to improved outcomes in children with respiratory disorders, yet, it is also responsible for significant complications (Greenough, Naik, Kinali, Dimitrou, & Baker, 1999; Yildizdas, Yapicioglu, [...]