<b><i>Background:</i></b> Obesity and overweight, including childhood obesity and overweight, pose a public health challenge worldwide. According to the available research findings, long-term interventions focusing on dietary behavior, physical activity, and psychological support are the most effective in reducing obesity in children aged 6–18 years. There are limited studies showing the financial effectiveness of such interventions. <b><i>Objective:</i></b> The objective of the present study was to evaluate cost-effectiveness of the 6-10-14 for Health weight management program using pharmacoeconomic indicators, i.e., cost-effectiveness analysis using the incremental cost-effectiveness ratio. <b><i>Methods:</i></b> We used anthropometric data of 3,081 children included in a 1-year-long intervention with a full financial cost assessment. <b><i>Results:</i></b> The cost of removing a child from the overweight group (BMI &#x3e;85th percentile) was PLN 27,758 (EUR 6,463), and the cost of removing a child from the obese group (BMI &#x3e;95th percentile) was slightly lower, i.e., PLN 23,601 (EUR 5,495). Given the obesity-related medical costs calculated in the life-long perspective, these results can be considered encouraging. At the same time, when comparing the total costs per participant with the costs of other interventions, it can be noted that they are similar to the costs of school programs containing more than 1 type of intervention. <b><i>Conclusions:</i></b> The 6-10-14 for Health program can be considered cost-effective. As a result of committing financial resources in the approximate amount of EUR 1,790 per child, around half of the children participating in the program have improved their weight indicators.