The soybean aphid (SBA) was first reported in Wisconsin during 2000. Currently, research in the Midwest has addressed the role of predators and climatic factors on SBA. On May 17, 2004, RoundUp® ready soybeans were planted in 17.78 cm. and 76.2 cm row spacing, at Rock Springs, PA. An randomized complete block design was used and consisted of four repetitions of the 17.78 cm. and 76.2 cm row spacing. Ten soybean plants were selected in each plot and a total of 40 soybean plants were examined in each row spacing. Throughout the season we counted all the aphids and predators on the experimental plants and recorded the total number of specimens per plant. These counts were taken twice a week. The SBA reached its highest density in the fourth week after detection and the natural enemies’ population also peaked in the fourth week, two days after the SBA’s peak. Strong correlation existed between the SBA and predator populations. There were no significant differences in SBA and natural enemies numbers between 17.78 cm. and 76.2 cm. row spacing.