The purpose of this work was to study the effect of hydrothermal, biological and photo degradation on natural fibres reinforced biodegradable starch-based (Mater-BiKE) composites to characterize the structural changes occurring under exposure to different environments. The composites water-uptake rate was hindered by the interfacial interactions between matrix and fibres. Thermal, structural and morphological analysis provided useful information about the irreversible changes in the properties of the composites caused by degradation in soil and photodegradation, and their synergetic effects. The effects due to the photo-oxidation and degradation in soil on the composites depended on the different chemical composition of each fibre. The composite with more hemicellulose and lignin in its formulation was more affected by both types of degradation, but still the end result properties were better than the ones shown for the degraded Mater-BiKE. The photo-oxidation of all the studied materials achieved enhanced degradation rate in soil. The Mater-BiKE/ kenaf was shown to have the slowest water-uptake rate and better thermal properties once photo-oxidized, indicating better service life conditions. At the same time, the Mater-BiKE/kenaf was affected to a major extent by the synergetic effects of both photo-oxidation and soil burial test, showing a faster degradative rate and better disposal conditions. © 2014 Scrivener Publishing LLC.