Rubella vaccine is not included in the Sudanese national immunization programme, and data on the prevalence of rubella among women of childbearing age are inadequate. The objective of this cross-sectional study was to determine the seroprevalence of rubella among pregnant women in Khartoum state, Sudan. A total of 500 pregnant women who visited 7 antenatal clinics from November 2008 to March 2009 were examined for the presence of rubella IgG antibodies using ELISA. Rubella IgG antibodies were detected in 95.1% (95% CI 93.2%–97.0%) of women. This seroprevalence was significantly associated with education level, but not with age, residence area, occupation or parity. We presume this high seroprevalence indicates a high circulation of wild rubella virus in Khartoum state. Similar studies in other Sudanese states would be important for informing a decision to introduce rubella vaccine to Sudan.