OBJECTIVES Studies of posttraumatic stress disorder (PTSD) document a significant proportion of cancer survivors reporting severe posttraumatic stress symptoms, even when they do not meet full diagnostic criteria. However, few studies have directly examined the clinical significance of these 'partial PTSD' symptoms in survivors. This study aimed to investigate the prevalence of PTSD symptoms in a cohort of long-term survivors of Hodgkin's lymphoma (HL) and to explore the clinical relevance of the partial PTSD phenomenon by assessing impairment of function secondary to sub-threshold symptomatology. METHODS The Posttraumatic Diagnostic Scale was completed by 105 HL survivors and 101 sibling controls. Survivors' age at time of participation ranged from 24 to 71 years, age at time of diagnosis ranged from 6 to 61 years, and the median time since diagnosis was 16 years (range = 7-34). RESULTS Posttraumatic stress disorder prevalence was not significantly higher in HL survivors (13%) compared with sibling controls (6.9%, p = 0.098). However, a significantly larger proportion of survivors (35.2%) met criteria for partial PTSD compared with siblings (17.8%, p = 0.004). Moreover, the majority of the survivors with partial PTSD (86.5%) reported experiencing some functional impairment related to these posttraumatic stress symptoms. CONCLUSIONS A significant number of HL survivors experience posttraumatic stress symptoms severe enough to result in functional impairment. This finding underscores the importance of future research detailing the psychological and functional outcomes in survivors with partial PTSD and of careful clinical practice that assesses for functional impairment secondary to partial PTSD symptomatology, in male and female survivors, even years after completion of therapy.