Background: Testing for illicit drugs may expose women who test positive to severe legal and social consequences. It is unknown whether racial disparities in drug testing practices underlie observed disparities in legal and social consequences of positive tests. Methods: Using administrative hospital and birth certificate data, we analyzed factors associated with both receipt and results of illicit drug testing among women with live births during 2002-2003. We assessed the independent association of race and other sociodemographic factors with both receipt of a drug test by the mother or her newborn infant and positive maternal or neonatal toxicology results, after controlling for obstetrical conditions and birth outcomes associated with maternal substance abuse. Results: Of the 8487 women with live births, 244 mother-newborn pairs (3%) were tested for illicit drug use. Black women and their newborns were 1.5 times more likely to be tested for illicit drugs as nonblack women in multivariable analysis. However, race was not independently associated with a positive result. Conclusions: We identified racial differences in rates of testing for illicit drug use between black and nonblack women. We found equivalent positively rates among tested black and nonblack women. The prevalence of drug use among untested women is unknown, however, so although tested women had equivalent rates of substance use detected, whether black and nonblack substance users are equally likely to be identified in the course of peripartum care. remains uncertain.