Abstract There is interest in the potential of Internet-delivered programs to cost-effectively increase access to pain management for people with chronic pain. However, few large-scale clinical and economic evaluations have been undertaken. Using a randomised controlled trial design, the current study (n = 659) examined the clinical efficacy, cost-effectiveness, and cost utility of an Internet-delivered pain management program for people with mixed chronic pain conditions when delivered with optional clinician support. The treatment group reported significant improvements in disability, depression, anxiety, average pain intensity, and quality-adjusted life years (QALYs), compared with control, and exhibited relatively high levels of treatment engagement and satisfaction. Each additional clinical improvement (defined as ≥ 30% improvement) produced by the intervention, over control, was associated with a cost of $48, $27, $38, and $83 for disability, depression, anxiety, and average pain intensity, respectively. Gaining one QALY was associated with a cost of $152 or $11,910 per QALY when an 80% probability criterion for cost utility was applied. The program itself was associated a relatively small, fixed, cost per patient but was not cost saving over the brief intervention period. The findings support the clinical efficacy and cost-effectiveness of Internet-delivered programs with “on demand” clinician support as a way to increase access to pain management. Key limitations of the current study include the use of a waitlist-control group, a short follow-up period, and the focus on governmental healthcare costs. Further evaluation of these programs is necessary if they are scaled up and offered as routine care.