Investigation of treatments that effectively treat adults with post-traumatic stress disorder from childhood experiences (Ch-PTSD) and are well tolerated by patients is needed to improve outcomes for this population. The purpose of this study was to compare the effectiveness of two trauma-focused treatments, imagery rescripting (ImRs) and eye movement desensitisation and reprocessing (EMDR), for treating Ch-PTSD. We conducted an international, multicentre, randomised clinical trial, recruiting adults with Ch-PTSD from childhood trauma before 16 years of age. Participants were randomised to treatment condition and assessed by blind raters at multiple time points. Participants received up to 12 90-min sessions of either ImRs or EMDR, biweekly. A total of 155 participants were included in the final intent-to-treat analysis. Drop-out rates were low, at 7.7%. A generalised linear mixed model of repeated measures showed that observer-rated post-traumatic stress disorder (PTSD) symptoms significantly decreased for both ImRs (d = 1.72) and EMDR (d = 1.73) at the 8-week post-treatment assessment. Similar results were seen with secondary outcome measures and self-reported PTSD symptoms. There were no significant differences between the two treatments on any standardised measure at post-treatment and follow-up. ImRs and EMDR treatments were found to be effective in treating PTSD symptoms arising from childhood trauma, and in reducing other symptoms such as depression, dissociation and trauma-related cognitions. The low drop-out rates suggest that the treatments were well tolerated by participants. The results from this study provide evidence for the use of trauma-focused treatments for Ch-PTSD.