Background: Hypothalamic-pituitary-adrenal (HPA)-axis dysregulation has inconsistently been associated with posttraumatic stress disorder (PTSD). Yet, trauma exposure rather than PTSD may be responsible for HPA-axis dysregulation. In two meta-analyses, we assessed the association of adulthood trauma exposure and HPA-axis functioning in healthy subjects with and without PTSD. Method: A literature search in Pubmed and PsychInfo, using keywords and MeSH terms such as cortisol, emotional trauma, and PTSD, was performed. Only studies that included mentally healthy trauma-exposed (TE) individuals as well as non-exposed (NE) healthy individuals and/or PTSD patients (PTSD) were selected. This resulted in 1511 studies of which ultimately, 37 studies (21 TE versus NE and 34 TE versus PTSD, N=2468) were included. Methodological quality of all studies was assessed according to specific quality criteria. Pooled effect sizes (Hedges's g) on cortisol levels were compared. For all analyses, random effect models were used. Results: Cortisol levels were neither significantly different between TE versus NE subjects (-0.029; 95%CI: -0.145; 0.088) nor between TE subjects versus PTSD patients (0.175; 95%CI: -0.012; -0.362). Subgroup analyses showed an increased cortisol suppression after the low dose dexamethasone suppression test (DST) in TE versus NE subjects (-0.509; 95%CI: -0.871; -0.148). This meta-analysis was limited by the fact that lifetime psychiatric illness and childhood trauma were not an exclusion criterion in all 37 studies. Conclusion: Neither adulthood trauma exposure nor PTSD were associated with differences in HPA-axis functioning, although adulthood trauma may augment cortisol suppression after the DST. More evidence on other dynamic tests of HPA-axis functioning in PTSD and adulthood trauma exposure is needed. © 2011 Elsevier Ltd.