The influence of sisal fibre content, peroxide cross-linking, and wax addition on the thermal properties of LDPE-sisal composites was investigated using differential scanning calorimetry and thermogravimetric analysis. It was found that the presence of wax and sisal fibre, as well as peroxide treatment, has an effect on the LDPE crystallinity. In the presence of sisal, the melting temperature of peroxide treated samples decreases substantially, and this decrease becomes more pronounced with increasing sisal content. The presence of wax reduces the extent to which the melting temperature decreases. It was further found that the presence of wax and sisal fibre, as well as peroxide treatment, has an effect on the thermal stability of the composites. (C) 2004 Elsevier B.V. All rights reserved.