The proliferation of alarms on equipment in ICUs contributes to a level of noise that can disturb both patient and staff. To determine whether these alarms are identifiable by sound alone to our ICU staff, we recorded 33 audio signals commonly heard on the ward, 10 of which we defined as critical alarms. One hundred subjects (25 physicians, 41 nurses, and 34 respiratory therapists) listened individually in a quiet room to the tape recording that consisted of 10 s of audible followed by a 10-s pause for a written response. Only 50 percent of the critical alarms and only 40 percent of the noncritical sounds were correctly identified. By occupation, registered respiratory therapists scored highest, followed by nurses, nonregistered therapists, and physicians. Those with > 1 year ICU work experience scored higher than those with less than 1 year. We conclude that the myriad of alarms that regularly occur in the ICU are too much for even experienced ICU staff to quickly discern. Patient and caregiver alike could benefit by a graded system in which only urgent problems have audible alarms, and these should be covered by regular in-service training.