Physical and engineering properties of paddy seeds plays a crucial role in designing and development of drum’s orifice shape and size in drum seeder. The physical and engineering properties of dry, soaked (12 hours soaking) and pregerminated (24 hours soaking + 12 hours incubation) paddy (Bsmati-370) seeds were studied to finalize these dimensions. The average value for; length, width, thickness and equivalent diameter (mm) varies from 9.95 to 10.55, 10.98 to 11.61, 12.01 to 12.53 mm; 1.95 to 2.12, 2.41 to 2.57, 2.67 to 2.90 mm; 1.70 to 1.74, 2.06 to 2.18, 2.29 to 2.48 mm; and 3.07 to 3.20, 3.55 to 3.68, 3.81 to 4.11 mm for dry, soaked and pre germinated seeds respectively. The aspect ratio and sphericity were found to be 0.19, 0.24, 0.28 and 30, 32.88 and 34.70% for dry, soaked and pregerminated seeds respectively. There was an increase in volume, aspect ratio and terminal velocity by 21, 26.31 and 15.31 % and 39.98, 47.36 and 18.91% for soaked seed and pre germinated seed over the dry seed respectively.