SAB assays have increased the sensitivity and specificity to detect HLA alloantibodies, but there is uncertainty about the clinical relevance of SAB-positive alloantibodies when the FCXM is negative. We performed a retrospective study to evaluate the clinical significance of SAB-detected DSA in 82 pediatric recipients of a first kidney transplant between January 2000 and December 2005 who had a negative pretransplant FCXM. Pretransplant sera were evaluated by SAB for DSA. Graft loss and rejection between patients with (DSA+) and without DSA (DSA-) were compared. DSA were detected in 13.9%. Eighty percent of DSA+ subjects were DD transplant recipients vs. 56.9% in the DSA- cohort. The RR of graft loss in DSA+ vs. DSA- was 3.3 (95% CI, 1.4-7.9) and in DD was 4.3 (95% CI 1.4-13.1). By Cox regression, the HR of graft loss in DSA+ vs. DSA- was 2.8 (95% CI 0.7-10.9; p = 0.14) and in DD was 5.1 (95% CI 1-25.6; p = 0.05). Acute rejection occurred in 60% in the DSA+ vs. 44.4% in DSA- (p = 0.5). SAB-detected DSA was associated with impaired renal allograft survival in pediatric renal transplant recipients. Impaired graft survival in pediatric renal transplant recipients with DSA detected by solid-phase assays.