Background and Objectives: Although immunoglobulin (Ig) preparations including RhIg have been noted for their record of safety, recent reports of hepatitis C virus (HCV) transmission by some Ig preparations have raised concern. This analysis examined the safety of RhIg manufactured in the US by comparing the prevalence and incidence of viral markers in Rh–negative and Rh–positive female blood donors. Materials and Methods: Demographic and viral marker data were analyzed for allogeneic donations collected from female donors of childbearing age (17–49 years of age) from April 1992 to May 1996. Prevalence and incidence rates were calculated for HCV, human immunodeficiency virus (HIV), and hepatitis B surface antigen (HBsAg). Results: Of the 624,939 female donors included in the study, 96,355 (15.4%) were Rh–negative and 528,584 (84.6%) Rh–positive. There were no significant differences in the prevalence of HCV and HIV between Rh–negative and Rh–positive female donors. HBsAg prevalence was significantly higher among non–white compared to white donors. Following implementation of the more sensitive EIA 2.0 screening test for HCV in April 1992, prevalence and incidence rates declined over time at similar rates for Rh–negative and Rh–positive female donors. Conclusions: Rh–negative female donors had similar prevalence and incidence rates for most viral markers compared to Rh–positive female donors. This analysis supports the historical safety of RhIg.