This paper deals with a structural design of a mold for making a composite ring of external circular fixator used in medical applications. It also focuses on the choice of technology and material for the production of a fixator ring. Due to the high demands on the quality, appearance, material of the product and higher series production, prepreg compression molding was chosen for this purpose. Thanks to this sophisticated production process, the high quality and accuracy of the ring can be achieved. The starting material for the production of composite components is a layer of resin-saturated fibers, abbreviated prepreg. This blank is cut on a CNC plotter and embedded into a mold for molding. The aluminium mold is provided with a separator and a filler of pores. The result of this contribution is the design of the mold to obtain the resulting product of the required mechanical properties, functional requirements and appearance.