Recently, the application of natural calcium sources from waste materials has been considered as a new trend for biodiesel production [12]. In this work, we have carried out transesterification using the duck and chicken eggshell wastes as inexpensive and environment-friendly catalyst. The objective was to optimize the process for biodiesel production from palm oil using CaO catalyst. The effects of reaction time, reaction temperature, methanol/oil molar ratio, catalyst loading, and reusability of catalyst were systematically investigated.