Purpose: Little is known about the trajectory of post-traumatic stress disorder (PTSD) symptoms in cancer survivors, despite the fact that such knowledge can guide treatment. Therefore, this study examined changes in PTSD symptoms among long-term survivors of non-Hodgkin's lymphoma (NHL) and identified demographic, clinical, and psychosocial predictors and correlates of PTSD symptomatology. Patients and Methods: Surveys were mailed to 682 NHL survivors who participated in an earlier survey and now were at least 7 years postdiagnosis. Information was obtained regarding PTSD symptoms, positive and negative perceptions of the cancer experience (ie, impact of cancer), and other potential correlates of PTSD. Results: A total of 566 individuals participated (83% response rate) with a median of 12.9 years since diagnosis; respondents were 52% female and 87% white. Although half (51%) of the respondents reported no PTSD symptoms and 12% reported a resolution of symptoms, more than one-third (37%) reported persistence or worsening of symptoms over 5 years. Survivors who reported a low income, stage ≥ 2 at diagnosis, aggressive lymphoma, having received chemotherapy, and greater impact of cancer (both positive and negative) at the initial survey had more PTSD symptoms at follow-up. In multivariable analysis, income and negative impacts of cancer were independent predictors of PTSD symptoms. Conclusion: More than one-third of long-term NHL survivors experience persisting or worsening PTSD symptoms. Providers should be aware of enduring risk; early identification of those at prolonged risk with standardized measures and treatments that target perceptions of the cancer experience might improve long-term outcomes. © 2011 by American Society of Clinical Oncology.