Alterations in coagulation, inflammation and immunity are associated with major injury. As platelets have both coagulation and immune functions, the aim of this study is to correlate platelet activation with the immunoinflammatory response in trauma and burn patients. Blood samples were drawn from trauma and burn patients and healthy volunteers. Platelet (sCD40L) and coagulation (D-dimers) activation, cytokines and inflammatory markers were assessed. sCD40L, D-dimers and cytokines were elevated in both injury groups. Overall, sCD40L levels correlated with interleukin (IL)-6 and tumour necrosis factor-alpha. Subanalysis revealed a correlation between sCD40L and IL-17a in the healthy volunteers and burn groups, but not the trauma group. A parallel activation of platelets and the inflammatory response occurs postinjury. However, in trauma patients, a potential critical interrelationship between platelet activation and the Th-17 response appears to be lacking, which may contribute to coagulopathic and immunoinflammatory complications and warrants further study.