Twenty three adolescents with a history of cancer, 27 physically abused adolescents, and 23 healthy, nonabused adolescents were administered structured posttraumatic stress disorder (PTSD) interviews and self-report questionnaires regarding family functioning. Thirty five percent of adolescent cancer subjects met criteria for lifetime PTSD as compared to only 7% of the abused adolescents: 17% of the cancer subjects and 11% of the abuse subjects met criteria for current PTSD. Adolescents with cancer viewed their mothers and fathers as significantly more caring and more protective than the comparison and abused adolescents. Cancer subjects who met criteria for lifetime PTSD save their families as significantly more chaotic than those who did not have PTSD. Eighty three percent of cancer subjects who had lifetime PTSD also had mothers who had PTSD.