This study is focused on recycling potential of some waste materials, such as olive pits, i.e. the solid phase derived from an olive oil mill, blended with thermoplastic polymers and used for the production of new materials applied in manufacturing containers and formworks. The olive pit powders are described and characterized. Then the powder is introduced in a bio-based and biodegradable matrix (polylactic acid, PLA) at various percentages. In this study, a comparison of the size distribution and the densities of olive pit powders according to the grinding methods (planetary mill and centrifugal mill) was made. The analyses showed that olive pits can be further studied as additive for the production of green materials. The development of an agricultural based polymer matrix compatible with olive pits and consequently a fully biodegradable composite system is the future and ultimate goal of the research undertaken. For that purpose, composite samples made out of PLA matrix, reinforced with olive pit powders were manufactured and mechanically characterized. With filler loading, an increase in the tensile modulus but a decrease of the flexural strength may be due to the poor interfacial bonding between olive pit powder and PLA.