The aim of this research is to study some physical and mechanical properties of cucumber fruits for seed production, to help the design of handling machines. The physical and mechanical properties are incorporated in the development of the seed-extraction machine as a case study. The main results in this study can be summarized as follows: Physical properties of cucumber fruits: diameter = 52.15 – 229.5 mm, length = 52.15 – 68.87 mm, mass = 273.8 – 470.4 g, volume = 380 - 860 cm³, projected area = 250 - 500 cm², real density = 0.94 -1.10 g/cm³, bulk density = 0.41 g/cm³, sphericity =  3.13 – 3.77. Mechanical properties: cucumber-fruit firmness = 64 – 100.9 N/cm², the axial cutting- force = 30  - 70 N. The physical and mechanical properties are incorporated in the design of seed-extraction machine is given also in the paper as a case study.