The aim of this study was to examine the effect of both promoter and intron polymorphisms of the serotonin transporter (5HTT) gene on posttraumatic stress disorder (PTSD) development. For this purpose, two polymorphisms of the 5-HTT gene, which are found in the promoter (5-HTT gene-linked polymorphic region) and second intron (variable number of tandem repeats) of the gene, were analyzed in 100 patients who were admitted to the Emergency Department after a mild physical trauma. None of the 5-HTT polymorphisms studied have an effect on PTSD development after a mild physical injury, but having L allele for 5-HTT gene-linked polymorphic region may cause milder hyperarousal symptoms in those patients who have developed PTSD.