High levels of exposure and occupational stress of first responders may have caused children in first-responder families to become traumatized following the September 11th, 2001 terrorist attacks. New York City public school children (N = 8,236) participated in a study examining mental health problems 6 months after the World Trade Center attack. Results revealed that children with emergency medical technician (EMT) family members had a high prevalence of probable posttraumatic stress disorder (PTSD; 18.9%). Differences in rates of probable PTSD among EMTs' and firefighters' children were explained by demographic characteristics. Where EMTs are drawn from disadvantaged groups, one implication of this study is to target EMT families in any mental health interventions for children of first responders.