An attempt was made to establish relationships between the physical properties of the seeds, expressed from the rheological behaviour, and their grinding behaviour, i.e., the particle size distribution and the specific energy requirement during grinding. The rheological behaviour of the seeds tested (horse bean, pea, lupine, and vetch) with different moisture content was measured with a traction-compression Instron apparatus on individual seeds. The motion of the piston was registered as well as the applied force and consequently different thresholds were defined and parameters were established. A small commercial hammermill Culatti was used for steady-state continuous grinding experiments. A significant relationship was found between the characteristics of the compression curve and the grinding energy requirement.