The castor beans biodiesel by-products total 66.5% of the castor bean mass: hulls and cake weigh 25 and 37.5% of the mass, respectively; glycerin, the by-product of the biodiesel production, 3.25%. The castor oil biodiesel by-products presented the following high heating values: hull 16.1 MJ/kg; cake 21.9 MJ/kg; and the glycerin 21.5 MJ/kg. The energy balance showed that the by-products represented 49% of the total energy, while the biodiesel 51%. This work shows the thermodynamic characteristics of the castor oil biodiesel by-products and the importance of their use to reduce the operational costs of the castor oil biodiesel plant.