Circular economy imposes to think of innovative ways to reduce the amount of energy consumed as well as the amount of waste produced by the construction sector. This study delves into the development of a novel composite material synthesized from marble slurry and discarded fishnets, offering a sustainable solution to two major environmental pollutants. The choice of these types of waste lies behind the fact that they are both extremely polluting, and that they are available in consistent amounts. Furthermore, the legislation concerning the disposal of these two types of waste is either lacking or improperly followed, making it difficult to fully assess the magnitude of their environmental impact. However, research on such composite materials – especially in construction sector – is still almost unexplored, leaving the possibility to create something innovative as well as environmental-friendly. The marble slurry acts as filler in the polymeric matrix, in the attempt to enhance the properties of the polymer, making the resulting composite a suitable material for construction use. The material was fabricated by combining finely ground marble waste with recycled polymer fibers extracted from disposed fishnets, both locally collected, forming a composite material through three processes: extrusion, thermal compression molding and FDM 3D printing. Although preliminary results suggest promising mechanical properties, including high elastic modulus, the study is still in its early stages, and further testing is required to comprehensively assess the material’s long-term performance, environmental resistance, as well as potential applications.