This work investigates composites of biodegradeable polylactide (PLA) reinforced with graphite fillers: graphite flakes (A) and amorphus graphite (B). Composites were prepared in a Brabender mixer (filler concetration: 0.1, 0.5, 1 and 5 wt. %) and by solution mixing (with 0.1and 1 wt. % of filler). Mechanical and thermal properties of pure polylactide and its composites were investigated. An insight into phase transition temperature and phase transition of the polymer were obtained by differental scanning calorimetry. The thermal stability of the samples was monitored by thermogravimetry. The contact angles of test liquids (water, formamied and diiodomethane) were determined by a goniometer after which the free surface energy was calculated. The universal testing machine was used to determine mechanical propertise of PLA and prepared composites. The tensile strenght, Young's modulus and elongation at break of the materials were determined. Characterization of composite materials revealed that the addition of fillers to polylactide has different influence on some of its properties. The DSC method has shown influence of various preparation methods and different fillers on the glass transition temperature, which did not change significantly, though. Thermogravimetry has showed that the composites are more thermally stable than pure PLA. Composites have better mechanical properties such as higher Young's modulus, tensile strenght as well as elongation at break. Studies on the goniometer did not give a clear correlation between the type and concentration of filler in the composite and its surface properties.