This research represents the first controlled treatment study of hypnosis and cognitive behavioural therapy (CBT) of acute stress disorder (ASD). Civilian trauma survivors (n = 87) who met criteria for ASD were randomly allocated to six sessions of CBT, CBT combined with hypnosis (CBT-hypnosis) or supportive counselling (SC). CBT comprised exposure, cognitive restructuring and anxiety management. CBT-hypnosis comprised the CBT components with each imaginal exposure preceded by a hypnotic induction and suggestions to engage fully in the exposure. Fewer participants in the CBT and CBT-hypnosis groups met criteria for post-traumatic stress disorder at post-treatment and 6-month follow-up than those in the SC group. CBT-hypnosis resulted in a greater reduction in re-experiencing symptoms at post-treatment than CBT.