Objective: Alexithymia is hypothesized to be a stable trait that hinders favourable outcomes of psychotherapy. We tested two hypotheses: i) alexithymia is not stable but changes along with a change in depressive symptoms and ii) pretreatment alexithymia hinders gaining benefits from psychotherapy. Method: A total of 201 participants (mean age = 54 years, SD = 4.4) with subthreshold depression were treated with cognitive behaviour therapy. Outcome was defined as the change in depressive symptoms from pretreatment to post-treatment and to 1-year follow-up. Results: Changes in depressive symptoms were significantly correlated with changes in alexithymia. Baseline alexithymia scores were not correlated with treatment outcome. Conclusion: Alexithymia is less stable than hypothesized: changes in alexithymia were associated with change in depressive symptoms. Furthermore, alexithymia does not hinder cognitive behaviour therapy outcome. Copyright © 2008 The Authors.