Stereolithography, one of the additive manufacturing techniques, was used to fabricate monolithic catalyst carriers the photosensitive resin Ceramic resin. During the experimental part of the work, structured monolithic catalyst carriers were prepared, which were then used for the catalytic oxidation of toluene. A catalytically active component (MnFeOx) was previously applied to the fabricated structured carrriers by wet impregnation. A total of 7 functional samples of 3D-printed monolithic catalyst carriers were made in order to describe the influence of different ratios of Mn and Fe in the catalytically active layer on the catalytic oxidation of toluene. The results of the adhesion test of the catalytic layer on the monolithic supports showed excellent results with very small deviations after 20 minutes of exposure to ultrasound at an operating frequency of 37 kHz for 20 minutes. The efficiency of individual monolithic catalysts was monitored by gas chromatography. The conversions of toluene were measured at different temperatures and the values T10, T50, and T90 were determined, corresponding to the temperatures at which conversions of 10%, 50%, and 90% were obtained. It was found that the complete conversion of toluene on the prepared monolithic catalysts is achieved at temperatures between 200 and 240 °C. It was also found that the maximum efficiency of the mixed oxide MnFeOx can be achieved by optimization of the preparation conditions and careful choice of the ratio of Mn and Fe. The monolithic catalyst with the ratio Mn:Fe = 2:1 proved to be the most effective.