The present study examined the relationships between memories for a single incident traumatic event - the 9/11 attack on the World Trade Center (WTC)--and posttraumatic stress disorder (PTSD). 2641 disaster restoration workers deployed at the WTC site in the aftermath of the attack were evaluated longitudinally, one year apart, for PTSD, using clinical interviews. Their recollection of the traumatic events was also assessed at these times. The results showed that recall of traumatic events amplified over time and that increased endorsement of traumas at Time 2 was associated with more severe PTSD symptoms. It was also shown that, of all the exposure variables targeted, memory of the perception of life threat and of seeing human remains were differentially associated with PTSD symptoms. Implications of the results are also discussed.