This chapter focuses on semi-crystalline, aliphatic polyamides, which are especially employed in injection molding, extrusion, and thermoforming. Almost all bio-based polyamides are commercially available as compounds with corresponding filling materials. Furthermore, lignocellulose is considered another promising, future raw material source for bio-based polyamides and other plastics, because it is available in large amounts, and also does not compete with foods, such as corn or rapeseed. Furthermore, as was also the case for petro-based polyamides, the macroscopic properties of bio-based polyamides are dependent on the monomers and their number of C-atoms. In glass fiber composites, this leads to mechanical properties that are less moisture-dependent. Composites that contain regenerated cellulose fibers display an increased impact strength, and have a weakened strength and E-modulus when wet due to fibers swelling with moisture, and due to a higher level of elongation-at-break.