This article focuses on wear tests of spur gears made with the use of additive manufacturing techniques from thermoplastic materials. The following additive manufacturing techniques were employed in this study: Melted and Extruded Modelling (FDM) and Fused Filament Fabrication (FFF). The study analysed gears made from ABS M-30 (Acrylonitrile Butadiene Styrene), ULTEM 9085 (PEI Polyetherimide) and PEEK (Polyetheretherketone), and the selection of these materials reflects their hierarchy in terms of economical application and strength parameters. A test rig designed by the authors was used to determine the fatigue life of polymer gears. Gear trains were tested under load in order to measure wear in polymer gears manufactured using FDM and FFF techniques. In order to understand the mechanism behind gear wear, further tests were performed on a P40 coordinate measuring machine (CMM) and a TalyScan 150 scanning instrument. The results of the gear tests made under load allow us to conclude that PEEK is resistant to wear and gear train operating temperature. Its initial topography undergoes slight changes in comparison to ABS M-30 and Ultem 9085. The biggest wear was reported for gears made from Ultem 9085. The hardness of the material decreased due to the loaded gear train's operating temperature.