High shoot-ureide concentrations are reportedly associated with soybean genotypes having dinitrogen fixation that is sensitive to water deficits. Shoot ureides are generally linearly related to shoot N in well-watered soybean, with low-ureide genotypes also having low shoot N, but previous research indicates some genotypic variation in this relationship. This research attempts to identify high-N genotypes with potentially drought-tolerant dinitrogen fixation. Shoot N and ureide concentrations were evaluated in the field under well-watered conditions for 30 soybean genotypes at two harvest dates during reproductive development at Fayetteville, AR in 2006 and 2007. Linear regression of shoot ureide versus shoot-N concentrations had r-squared values of 0.31 and 0.57 for the two harvests in 2006. The cultivar CNS had high N concentrations and low ureides in the shoot at both harvests in 2006. Also in 2006, Xylem sap collected from a subset of 10 genotypes indicated that ureide-N, amino-N, and nitrate-N accounted for greater than 90% of total xylem N in these lines, but was not a good indicator of total shoot N or shoot ureide concentrations.