This graduate thesis describes in detail the process of making a prototype remote-controlled lawn mower. The individual components are listed, the construction method is shown and the testing of the prototype has been conducted. The thesis also deals with the issue of positioning the components on the lawn mower’s body and a proper selection of components that are mutually compatible according to specifications, strength, dimensions, weight and power. All the parts together form a unique assembly, i.e. a finished product ready to cut grass. Most of this project has been done using CATIA software tool based on the course 3D computer designing 1. Purchased mower components were measured with measuring instruments and without additional designs have been modeled in a 1:1 ratio within PART MECHANICAL DESIGN software. The prototype is shown with all parts; from a petrol engine and mower’s drive parts, to the 3D model of the remote controller. Using the MECHANICAL ASSEMBLY DESIGN software tool, everything has been positioned into a unique assembly and modeled; the chassis, the load-bearing parts and the holders of components such as bearings, axles and gear reducer. The following metalworking procedures were used during the manufacture of the mechanical parts of the mower: laser and plasma cutting, turning work, drilling, milling, and grinding. Joining the steel parts together has been done by MIG welding process. A protective paint coating has been applied on metal surfaces to protect against corrosion. The chassis has been prepared for hot dip galvanizing and plasticizing for long-lasting protection and aesthetics. After the development of the prototype, for the purpose of final implementation, testing of individual subsystems has been performed using the remote controller; mower’s drive, petrol engine gas regulation, fitting of the gear reducer unit to the blade and petrol engine shut-off switch.