The effects of moisture content on the physical properties of two varieties of Lablab purpureus (L.) sweet seeds, ‘Rongai', and ‘Highworth' were investigated. The physical properties investigated include length (L), width (W), thickness (T), arithmetic mean diameter, geometric mean diameter, equivalent diameter, sphericity, seed volume and weight, roundness, bulk density, particle density and porosity at moisture range of 9.7 to 29 % wet basis (w.b.) for ‘Rongai' and 10.2 to 22.6 % (w.b.) for ‘Highworth'. These properties are useful in the design of planting, harvesting, processing, handling and storage equipments. Results showed that the axial dimensions, arithmetic mean diameter, geometric mean diameter and equivalent diameter, individual grain mass, and volume increased with increasing moisture content. There was a decrease in roundness, bulk density and porosity with increasing moisture content.