Behavioural activation by non-specialists appears effective in the treatment of depression. We examined incremental cost-effectiveness of behavioural activation (n = 24) v. treatment as usual (n = 23) in a randomised controlled trial. Intention-to-treat analyses indicated a quality-adjusted life-year (QALY) difference in favour of behavioural activation of 0.20 (95% CI 0.01-0.39, P = 0.042), incremental cost-effectiveness ratio of £5756 per QALY and a 97% probability that behavioural activation is more cost-effective at a threshold value of £20,000. Results are promising for dissemination of behavioural activation but require replication in a larger study.