Limited quality of childbirth care in sub-Saharan Africa primarily affects the poor. Greater quality is available in facilities providing advanced management of childbirth complications. We aimed to determine whether Maternity Waiting Homes (MWHs) may be a tool to improve access of lower socio-economic women to such facilities. Secondary analysis of a cross-sectional hospital survey from Iringa District, Tanzania was carried out. Women who delivered between October 2011 and May 2012 in the only District facility providing comprehensive Emergency Obstetric Care were interviewed. Their socio-economic profile was obtained by comparison with District representative data. Multivariable logistic regression was used to compare women who had stayed in the MWH before delivery with those who had accessed the hospital directly. Out of 1072 study participants, 31.3% had accessed the MWH. In multivariable analysis, age, education, marital status and obstetric factors were not significantly associated with MWH stay. Adjusted odds ratios for MWH stay increased progressively with distance from the hospital (women living 6-25 km, OR 4.38; 26-50 km, OR 4.90; >50 km, OR 5.12). In adjusted analysis, poorer women were more likely to access the MWH before hospital delivery compared with the wealthiest quintile (OR 1.38). Policy makers should consider MWH as a tool to mitigate inequity in rural childbirth care.