Optimizations in manufacture of agricultural machinery not only provide significant material savings, but also provide significant savings in energy requirements of drive units of these machines. In this study, chopper and mixer auger of self-propelled mixer feeder and spreader with a vertical auger and 1.5 m3 capacity was optimized by using finite element method (FEM) of analysis. Auger design was performed with Solidworks software and stress analyses were performed with Static Analysis Module of the software. For auger tube analyses, St37 was selected as the material. Based on stress analysis results, auger tube dimensions were identified as 219 x 6 mm. The greatest stress (91.5 MPa) value was observed at bolted connections of the auger tube. Based on operational parameters for auger tube dimensions, safety coefficient was identified as 2.57.