An economic and environmentally friendly catalyst derived from waste freshwater mussel shell (FMS) was prepared by a calcination-impregnation-activation method, and it was applied in transesterification of Chinese tallow oil. The as-prepared catalyst exhibits a "honeycomb" -like structure with a specific surface area of 23.2 m(2) g(-1). The newly formed CaO crystals are major active phase of the catalyst. The optimal calcination and activity temperature are 900 degrees C and 600 degrees C, respectively. When the reaction is carried out at 70 degrees C with a methanol/oil molar ratio of 12:1, a catalyst concentration of 5% and a reaction time of 1.5 h, the FMS-catalyst is active for 7 reaction cycles, with the biodiesel yield above 90%. The experimental results indicate that the FMS can be used as an economic catalyst for the biodiesel production. (C) 2011 Elsevier Ltd. All rights reserved.