Microplastic fibers (MPFs) released from synthetic textiles have been found to be a major source of microplastic in the environment. There is increasing evidence available that MPFs released during washing were likely formed during the manufacturing stage. However, real-life use of textiles is often associated with textile-on-textile abrasion, and the first evidence is available that MPFs and finer microplastic fiber fragments (fibrils) are formed during abrasion. In this study, we characterized the formation of MPFs and fibrils from a representative set of 12 polyester textiles after abrasion tests conducted with a Martindale tester. We also investigated the influence of rub intensity and the extractability of MPFs and fibrils from the abraded fabrics. For all textiles, the MPFs extracted after abrasion showed the same diameter as the fibers in non-abraded textiles (10-20 μm), while the extracted fibrils were much thinner (3-5 μm). The variability in the structure of the different polyester textiles led to a broad range of MPF and fibrils extracted during the first wash after 5000 rubs. One gram of textile released between 4900 and 640,000 MPFs and between 0 and 350,000 fibrils with an average fibril/MPF ratio of 0.8. The total number of MPFs and fibrils formed during abrasion was positively correlated with the increase in the number of rubs up to 10,000 times. Visible pilling on the textile surface was an important indicator for the formation of MPFs and fibrils. Our study revealed that textile abrasion is a critical, realistic, and overlooked mechanism for the formation of MPFs and fibrils, as abraded textiles (after 5000 times rubs) can release more than ten times the number of MPFs and fibrils compared to washing only.