The soybean aphid (Aphis glycines) has become a very important pest of soybeans over a short period. Soybean plant introduction (PI) 567598B is a source of aphid resistance identified in an earlier study. Using resistant cultivars of soybean is the most efficient and environmentally friendly way of controlling soybean aphids. Molecular markers linked to genes for resistance to aphids may improve selection for resistant plants when developing resistant cultivars. The objective of this study is to identify quantitative trait loci (QTLs) underlying aphid resistance in PI 567598B. The mapping population consisted of 188 F2 individuals derived from the cross Titan x PI 567598B. Titan is a high yielding soybean cultivar but like most cultivars, is susceptible to aphids. Over 100 polymorphic simple sequence repeat (SSR) markers were used to genotype the population. To date, single marker analysis (SMA) identified six SSR markers associated with aphid resistance.