This paper deals with measurements of the specific heat capacity of plastic waste/fly ash recycled composite and its components using both a differential scanning calorimeter and sapphire disks as standard reference material. The measurement is carried out at temperatures below the melting point of the plastic component. The constant heating rates are set at 2, 5, and 10 K.min(-1). The specific heat capacity of the recycled composite increases from 1.3 to 1.6 kJ.kg(-1).K-1 with increasing the temperature from 305 to 360 K, when the heating rates are set at 2 and 5 K.min(-1). In addition, the deviation in the data is within +/- 3%. However, the data for 10 K.min(-1) are about 2% lower than those for 2 K.min(-1). The specific heat capacity is independent of the shape and mass of the recycled composite sample. The uncertainty for the specific heat capacity data of the recycled composite is estimated to be within +/- 4%. The specific heat capacity of the fire retardant is as large as that of the fly ash. In addition, the specific heat capacity of the recycled composite depends largely on the content of the plastic waste. (C) 2007 Wiley Periodicals, Inc.