This paper reported the optimization of biodiesel production from waste cooking oil catalyzed by solid ostrich-eggshell and chicken-eggshell derived CaO via transesterification process using response surface methodology (RSM) and Taguchi method. Quadratic polynomial equations were obtained for transesterification reaction. Independent variables i.e. molar ratio of methanol to oil (M:O), catalyst concentration, reaction temperature and reaction time were investigated. It was found that the most influential parameter on the biodiesel production was reaction temperature based on both RSM and Taguchi method. The optimum biodiesel yield of similar to 98% (ostrich eggshell) and similar to 96% (chicken eggshell) were achieved at M:O of similar to 10:1; catalyst concentration of similar to 1.5 %w/v; reaction temperature of 65 degrees C; and reaction time of similar to 2 h for RSM and Taguchi method, respectively. (C) 2017 Elsevier Ltd. All rights reserved.