Sexually transmitted diseases and their outcomes disproportionately affect non-Hispanic Blacks who also receive later prenatal care. We used a sample of low-income pregnant women insured by Medicaid to assess racial disparities in the receipt of first trimester prenatal care and any as well as early (by 2nd trimester) syphilis screening. We used an older but unique file of linked 1995 Georgia Medicaid claims and Pregnancy Risk Assessment Monitoring System (PRAMS) births (n = 1,096) to test the relative explanatory power of factors contained in administrative versus survey data. Using administrative data, we found non-Hispanic Blacks were less likely than non-Hispanic Whites to receive first trimester care but more likely to be screened. Adding in PRAMS survey data eliminated these differences. Having an outpatient department as usual source of care was a key factor. This may reflect unmeasured characteristics of minorities and their neighborhoods or differences in screening practices across provider settings.