This explorative study examines the effects of an internet-based cognitive-behavioural therapy for complicated grief on post-traumatic growth and optimism. The study is part of a larger randomized controlled trial described in Wagner, Knaevelsrud, and Maercker (2006). The patients were randomly assigned to either a treatment group (n = 26) or a waiting list control condition (n = 25). The internet-based intervention consisted of exposure to bereavement cues, cognitive reappraisal exercises, and a module on integration and restoration. A short form of the Post-traumatic Growth Inventory (PTGI), the Life Orientation Test-Revised (LOT-R), and measures of complicated grief and psychopathological outcomes were administered. Results indicate that post-traumatic growth increased in the treatment group. No treatment effect was found for optimism. These findings contribute to the growing literature on personal growth in psychotherapy.