Infection with cytomegalovirus (CMV) can cause severe complications for hematopoietic stem cell transplant patients. In addition to screening for maternal antibodies to CMV with FDA-approved assays, some cord blood banks also screen the actual cord blood sample for CMV nucleic acid before the stem cell transplantation. Researchers recently investigated screening procedures used for cord blood donors. In one group, salvia cultures were used to screen 30,308 newborns, and 41 (0.14%) were CMV positive. In a separate group, 4,712 neonates, all with CMV seropositive mothers, had their cord blood screened using a new qualitative PCR assay to detect CMV-DNA; 18 (0.38%) were CMV positive. All 59 CMV cases were asymptomatic at birth. Although all of the mothers were seropositive for CMV, only 7/59 mothers had detectable CMV based on real-time PCR. Surprisingly, CMV positive cord blood donors had higher CD34+ cells, levels of colony-forming units, and total nucleated red blood cells than control donors. Further research is needed to determine how these results relate to the success of hematopoietic stem cell transplants.