OBJECTIVE: To determine whether the frequency induction of labor (IOL) varies by day of the week based on maternal race/ethnicity. STUDY DESIGN: Gravid women in the US from 2007 to 2010 were stratified into <34, 34 to 36, 37 to 38 and 39 weeks. Multivariable analyses estimated the association between weekend delivery, race/ethnicity (categorized as non-Hispanic white, Hispanic white, black and 'other') and their interaction with induction. RESULT: After 34 weeks, induction was less likely on the weekend (P<0.01) and less likely in black, Hispanic or 'other' women relative to non-Hispanic whites (P<0.01). However, there was a significant positive interaction between race/ethnicity and weekend delivery (P<0.001). During the late preterm gestation, weekend IOL was greater in black women (odds ratio, 1.08). CONCLUSION: The difference in IOL by race/ethnicity increased with gestational age. This difference was least on the weekends.