The physical and mechanical properties of sweet lupin seeds is necessary for the design of equipment to handle, transport , milling , process and store the crop . The physical properties of sweet lupin seeds have been evaluated as a function of seed moisture content varying from 9.70 % to 26.53 % (db) . In this moisture range, seed  length , width , thickness and geometric diameter increased from 11.067 to 11.838 mm, 9.992 to 10.591 mm, 5.174 to 5.734 mm and 8.291 to 8.944 mm respectively, the sphyericity of seeds calculated at different moisture content increased from 74.75 to 76.25 % with increase in moisture from 9.70 % to 21.07 % and reduced to 75.66 % with further increase in moisture content to 26.53 %, the 1000 seed mass increased from 0.433 to 0.670 g , true and bulk densities and rupture force decreased from 1.342 to 1.211 g/cm³ and from 0.777 to 0.717-g/cm³ and from 212.50 to 105.23 N respectively , the angle of repose increased from 14.41 to 21.82°and angle of friction with galvanized iron surface  increased from 19.8 to 22.4° with increased in moisture content from 9.70 % to 26.53 % (d.b ) .