Studies were initiated to determine the effect of soybean population and row width on weed control, economic return, yield, and yield components. Field studies were conducted at three locations in 2004 and 2005. Herbicide treatments included a weed-free control and a postemergence (POST) application of glyphosate at 0.84 kg ae ha^-1 + ammonium sulfate (AMS) to 10 cm weeds. Soybeans were thinned to populations of 197,600, 296,400, and 444,600 plants ha^-1 at St. Charles, and 123,500, 185,250, and 308,750 plants ha^-1 at Clarksville and East Lansing prior to the V1 growth stage. Weed-free yield was greater when soybean was planted in 19 cm rows compared to 76 cm rows, regardless of population at St. Charles in 2004. At Clarksville and East Lansing, weed-free yield was greater when soybean was planted at the highest population of 308,740 plants ha^-1 compared to 123,500 plants ha^-1 in 19 and 38 cm rows in 2004. Pod number was greater when soybean was planted in 19 cm rows compared to 76 cm rows at 197,600 plants ha^-1. At Clarksville, annual grasses, redroot pigweed (Amaranthus retroflexus), and common ragweed (Ambrosia artemisiifolia) control with glyphosate 28 days after treatment was better in 19 and 38 cm rows at 185,250 and 308,750 plants ha^-1 compared to 76 cm rows in 2004. At Clarksville and East Lansing, the highest net return occurred in 19 cm rows at 308,750 plants ha^-1 for the glyphosate treatment. At St. Charles, the highest net return occurred when soybean was planted in 38 cm rows at 444,600 plants ha^-1 for the glyphosate treatment. The cost of seeding soybean at higher rates was recovered by greater soybean yield in weed-free conditions in 19 and 38 cm rows at 2 of the 3 locations in 2004.