Technical Abstract: Sicklepod (Cassia obtusifolia) is a weed species that has contaminated soybean and other crops. Although sicklepod continues to be a problem weed, the advent of herbicide-resistant soybeans has reduced the problem somewhat in the last few years. Sicklepod seed contains a gum of commercial interest in addition to protein and fat. An inexpensive process to enrich gum and protein contents of sicklepod seed is desirable for increased utilization and further processing. This study was conducted to determine whether fine grinding and sieving of sicklepod seed into separate fractions according to particle size could enrich gum and protein. Sicklepod seed was finely ground in a pin mill at different speeds, and the resulting ground seed was separated into various fractions according to particle size. Gum content increased with particle size, and protein content decreased with particle size. Fine grinding and sieving of sicklepod seed can enrich gum in the fraction with largest particle size and can enrich protein in the fraction with smallest particle size. Fine grinding and sieving of sicklepod seed can make further processing more economical.