One hundred children aged 4–15 years with stable upper limb fractures were randomized to receive either a biobased polyester cast (n=50) or a synthetic fiberglass cast (n=50). The primary outcome was patient satisfaction, measured using a structured questionnaire at the end of the casting period. Secondary outcomes included clinical outcomes such as loss of reduction, complications, and skin-related issues. Outcomes were assessed at cast removal approximately 3–4 weeks post-application. Overall, the study revealed that the biobased polyester cast provided equivalent clinical stability and significantly better patient satisfaction, with fewer skin complications. These findings suggest that the biobased polyester cast is a viable, eco-friendly alternative to synthetic fiberglass casts for pediatric fractures.