Background: Sleep problems are pervasive in people with schizophrenia, but there are no clinical guidelines about their treatment in this context. The Better Sleep Trial (BEST) concluded that cognitive behavioural therapy (CBT) for insomnia, suitably adapted for this population, is likely to be highly effective for improving sleep in patients with schizophrenia. However, the cost-effectiveness of this sleep treatment for patients with schizophrenia is unknown. Aim: To assess the potential cost-effectiveness of CBT in treating sleep disorders in patients with schizophrenia. Method: An economic evaluation was incorporated into the BEST study to establish the cost-effectiveness of CBT in addition to usual care in terms of costs per quality adjusted life year (QALY) gained. An NHS and societal perspectives were adopted, and a 6-month time-horizon was taken. Uncertainty was displayed on cost-effectiveness planes and cost-effectiveness acceptability curves. A value of information analysis was performed to estimate the benefits of obtaining further evidence. Results: The results of the economic evaluation of the pilot study showed that the treatment leads on average to a 0.035 QALY gain (95% CI: -0.016; 0.084) as well as £1,524 (95% CI: -10,529; 4,736) and £1,227 (95% CI: -10,395; 5,361) lower costs from the NHS and societal perspective, respectively. Thus, they indicate that CBT is likely to be the dominant alternative (i.e. higher benefits at lower costs). The monetary value of collecting more information about the impact of the CBT on costs and QALYs was estimated to be approximately £87 million. Conclusions: CBT for treating insomnia in people with schizophrenia is effective and potentially cost-effective. A large trial designed to facilitate a thorough economic evaluation is needed to provide clear evidence about its cost-effectiveness.