<p>This article analyses the manufacturing quality of a set of cycloidal gear produced from polyoxymethylene POM by injection moulding. The initial stage involved a literature review. The review was carried out from the perspective of both polyoxymethylene processing and the design of gears. The goal of this analysis was to obtain injection moulding parameters that would produce gears of the highest possible quality. In order to obtain a set of cycloidal gears, the injection process was carried out. In next stage the set was analysed in the terms of technological defects. The most serious defects turned out to be vacuum cavities inside the plastic mass of the gears. These defects are the result of the appearance of process shrinkage and should be eliminated. Total volume of defects was 308.27 mm³. To eliminate the defects, the diameter of the pinpoint gates ϕ_<i>p</i> was increased. After increasing the diameter of the pinpoint gates from ϕ_<i>p</i> = 0.5 mm to ϕ_<i>p</i> = 3&#xa0;mm, another injection moulding was performed in the modified mould. Increasing of diamerer ϕ_<i>p</i> resulted in a significant improvement in quality for the gear set. For the new gear set total volume of defects was 101.402 mm³. Total volume of defects turned out to be less even 65%. The improvement is in particular visible for the inner gear (<i>z</i>₁ = 6). The vacuum cavities within the inner gear were eliminated. It is crucial to eliminate processing defects on this gear, since it is the inner gear that is more heavily loaded in the set of cycloidal gears. The gear set is a very non-technological structure when it comes to injection moulding. The article proves that eliminating of defects is possible even with this type of design is possible. As a result the inner gear (<i>z</i>₁ = 6) was obtained as a thick-walled with thickness of 10.4-mm element which contains no significant defects.</p>