A thermoplastic molding composition obtainable from polylactic acid and fibers by the following process steps: a) mixing the following components, without using a solvent: A) 20 to 55 % (w/w) of at least one thermoplastic polylactic acid (PLA), B) 45 to 80 % (w/w) of natural fibers having a length of 0.1 to 100 mm selected from the group consisting of cotton fibers, kenaf fibers, jute fibers, flax fibers, hemp fibers, cellulosic fibers, sisal fibers, chitin fibers, keratin fibers and coir fibers and/or pre-treated fibers selected from the group consisting of pre-treated cotton fibers, kenaf fibers, jute fibers, flax fibers, hemp fibers, cellulosic fibers, sisal fibers, chitin fibers, keratin fibers and coir fibers, C) 0 to 60 % (w/w) of further polymer component(s), which differ from A), and D) 0 to 50 % (w/w) of one or more additive(s), which differ from A) to C), where the weight percents of components A to D add up to 100 % by weight; and b) heat treatment of the mixture obtained in step a), without using a solvent, with a temperature of 180° to 220°C for a period of less than 5 minutes; and c) cooling of the thermoplastic molding composition obtained in step b) below the glass transition temperature (Tg) of the molding composition leading to solidification of the molding composition. a) mixing the following components, without using a solvent: A) 20 to 55 % (w/w) of at least one thermoplastic polylactic acid (PLA), B) 45 to 80 % (w/w) of natural fibers having a length of 0.1 to 100 mm selected from the group consisting of cotton fibers, kenaf fibers, jute fibers, flax fibers, hemp fibers, cellulosic fibers, sisal fibers, chitin fibers, keratin fibers and coir fibers and/or pre-treated fibers selected from the group consisting of pre-treated cotton fibers, kenaf fibers, jute fibers, flax fibers, hemp fibers, cellulosic fibers, sisal fibers, chitin fibers, keratin fibers and coir fibers, C) 0 to 60 % (w/w) of further polymer component(s), which differ from A), and D) 0 to 50 % (w/w) of one or more additive(s), which differ from A) to C), where the weight percents of components A to D add up to 100 % by weight; and A) 20 to 55 % (w/w) of at least one thermoplastic polylactic acid (PLA), B) 45 to 80 % (w/w) of natural fibers having a length of 0.1 to 100 mm selected from the group consisting of cotton fibers, kenaf fibers, jute fibers, flax fibers, hemp fibers, cellulosic fibers, sisal fibers, chitin fibers, keratin fibers and coir fibers and/or pre-treated fibers selected from the group consisting of pre-treated cotton fibers, kenaf fibers, jute fibers, flax fibers, hemp fibers, cellulosic fibers, sisal fibers, chitin fibers, keratin fibers and coir fibers, C) 0 to 60 % (w/w) of further polymer component(s), which differ from A), and D) 0 to 50 % (w/w) of one or more additive(s), which differ from A) to C), where the weight percents of components A to D add up to 100 % by weight; and b) heat treatment of the mixture obtained in step a), without using a solvent, with a temperature of 180° to 220°C for a period of less than 5 minutes; and c) cooling of the thermoplastic molding composition obtained in step b) below the glass transition temperature (Tg) of the molding composition leading to solidification of the molding composition. <EOS>