The authors examined ratings on four scales of alexithymia in 45 patients in four groups: Vietnam verterans in inpatient (Inpt-PTSD) or outpatient (Outpt-PTSD) treatment for posttraumatic stress disorder (PTSD), patietns on a medical service with somatic illnesses that have been the subject of psychosomatic research (Somatic), and a comparison group of psychiatric inpatients with a diagnosis of affective disorder (Affective). The data suggest a greater degree of alexithymia in the Input-PTSD and Somatic samples than in the Affective patients. In addition, the Input-PTSD and Somatic groups exhibited a similer degree of alexithyimia. This study also introduces a novel measure of alexithymia, the Alexithymia Provoked Response Questionnaire (APRQ), which showed a high degree of interrater reliability and a greater degree of correlation with the Beth Isreal Psychosomatic Questionnaire (BIPQ) than a MMPI subscale or the Schalling-Sifneos scale.