To assess the prevelance of probable post-traumatic stress disorder (PTSD) among different age groups in different residential areas and to investigate the relationship between the PTSD symptoms and the demographic characteristics after November 2003 Bombing Attacks in Istanbul. A hundred and seven injured participants who had applied to the local police stations and overall 420 subjects including the students, teachers and staff of a highschool quite near to the bombing area were participated to the study. All the participants were evaluated with Kocaeli - Brief Traumatic Stres Questtionnaire. The prevelance of probable PTSD was 5.9% in the students and 26.1% in the adults of the school sample. PTSD was found in 11.2% of female and 5.4% of male students. Core symptoms of PTSD, except hyperarousal, and help seeking behaviour were reported higher in adults than the students. Probable PTSD was found in 29.9% of police stations' appliers. PTSD symptoms, probable PTSD diagnosis and help seeking behaviour was not statistically different between adults in the school and adults applied to police stations. However, probable PTSD was higher in adults with lower education. After the terrorist events, it is important to determine risk groups and to establish community based mental health services.