In order to optimize the design and working parameters of agricultural machinery related to harvesting, knowledge about the physical properties and mechanical behaviour of harvest-ready maize is required. Previous studies have been conducted on different maize varieties from different parts of the world in different growing seasons. However, these experiments were usually conducted on dried or deep-frozen samples and therefore the condition of these samples was not related to the harvested material. In order to produce more relevant experimental results, a complex measurement method that involves in-situ observations and laboratorial experiments was established after taking into consideration the process of maize harvesting with a combine harvester and a maize header. The measurement method was successfully conducted over a period of days of harvesting in Hungary. With regard to the physical properties of the stalk, the distribution of the internodal diameter and the length, mass and moisture content of the stalk were determined. The mechanical behaviour of the stalk was analysed through transversal compression, three-point bending and dynamic cutting experiments. The results clearly demonstrate that the physical properties (diameter, length and wet-mass ratio, moisture content) and mechanical properties (force response characteristic and required mechanical work) of different parts of the maize stalk vary significantly. Therefore, different parts of the maize stalk require different considerations during machine development.