OBJECTIVES: Parenting programs are effective in reducing child conduct problems (CP) but there are no cost-effectiveness analyses (CEA) comparing different programs within the same RCTThis study aimed at conducting a CEA of an RCT where the group-based parenting programs: Comet, Incredible Years (IY), Cope and Connect, and bibliotherapy were compared to a waitlist control with a time horizon of 4 months from a government payer perspective targeting CP in children aged 3-12 years. METHODS: The study samples consisted of 961 parents of 3-12 year-old children with CP, including 862 who started a program or reading a book, and 159 in the waitlist. CP were measured by the Eyberg Child Behavior Inventory (ECBI). Effectiveness was expressed as the proportion of “recovered” cases of CP based on the Reliable Clinical Change Index. Intervention costs and parents’ time costs are reported. A CEA was performed comparing costs and effects between interventions that showed differences in outcomes and a cost-minimisation where outcomes were similar. RESULTS: All programs apart from Connect were effective in improving CP. Comet showed significantly higher proportion of recovered cases than the bibliotherapy (29.7% vs 17.4%) and higher costs. The CEA delivered an incremental cost-effectiveness ratio for Comet versus bibliotherapy of US$8594 per one recovered case of CP. The cost-minimisation delivered an average cost per recovered case of US$585 for the bibliotherapy, US$2445 for Cope and US$6624 for IY.  CONCLUSIONS: In the absence of a willingness-to-pay threshold, bibliotherapy is the cheapest option to achieve minimal significant effects and could be a low-cost and easily delivered alternative within a limited budget. If decision-makers are willing to make larger investments Comet is the best alternative. Further studies are needed with longer follow-ups to ascertain on the sustainability of effects and a full economic evaluation to help decision-makers set priorities across different interventions.