Physical and mechanical properties of alfalfa grind are required for optimum designing of equipments that are being used in traorting, processing, storage and size reduction of the crop. Understanding the energy requirement for alfalfa size reduction would be important for downstream processing such as densification. This study was conducted to determine the effect of particle size (2.38, 3.36 and 4.76 mm) and moisture content (8, 9.3 and 11%, w.b.) on bulk density, coefficient of static friction, angle of repose, coefficient of internal friction, cohesion, coefficient of wall friction and adhesion (on polished steel) of alfalfa grinds. Tests were conducted using factorial experiment in completely randomized design. Cohesion and coefficient of internal friction with hammer mill screen sizes of 2.38 and 3.36 at moisture content of 9.3% w.b. were determined at two different vertical load ranges. Coefficient of internal friction and cohesion, and adhesion on polished steel plat were determined using a direct shear tests coefficient of static friction was determined using a sloped surface. Results showed that the particle size and moisture content had significant effect ( P 0.0001) on all measured physical and mechanical properties. With an increase in moisture content, bulk density, angle of reposes, coefficient of static friction and cohesion increased, whereas coefficient of internal friction and adhesion decreased. With an increase in particle size, the bulk density, cohesion and adhesion were decreased, while the other properties were increased. The values of strength parameters depended upon the range of normal stresses used in the tests. The bulk density of alfalfa grind varied from 161.6 to 202.2 kg m- 3 . The coefficient of static friction against three surfaces changed from 0.34 to 0.87; the highest and lowest values were obtained on rubberand Plexiglas surface respectively. Larger particle with higher moisture content had the highest angle of repose (54.5°). The alfalfa grind prepared with the 2.38 mm screen size at moisture content of 11% w.b., and 4.76 mm screen size at moisture content of 8% w.b. had the highest and lowest cohesion (7.65 and 4.80 kPa), respectively. Alfalfa bales were chopped using a chopper equipped with a screen size of 20 mm. The alfalfa chops were then divided into three portions. The first portion was left un-sieved, whereas the second and third portions were passed through 18 and 15 mm sieve sizes, respectively. Each portion was ground separately, using a hammer mill with four different screen sizes (1.68, 2.38, 3.36 and 4.76 mm). Energy data were collected using a developed Wattmeter and a data acquisition system. Effect of four grind sizes for each size of alfalfa chop was considered using a completely randomized design. Results showed that the screen size in the hammer mill had signifi