Access to appropriate health care including skilled birth attendance at delivery and timely referrals to emergency obstetric care services can greatly reduce maternal deaths and disabilities, yet women in sub-Saharan Africa continue to face limited access to skilled delivery services. This study relies on qualitative data collected from residents of two slums in Nairobi, Kenya in 2006 to investigate views surrounding barriers to the uptake of formal obstetric services. Data indicate that slum dwellers prefer formal to informal obstetric services. However, their efforts to utilize formal emergency obstetric care services are constrained by various factors including ineffective health decision making at the family level, inadequate transport facilities to formal care facilities and insecurity at night, high cost of health services, and inhospitable formal service providers and poorly equipped health facilities in the slums. As a result, a majority of slum dwellers opt for delivery services offered by traditional birth attendants (TBAs) who lack essential skills and equipment, thereby increasing the risk of death and disability. Based on these findings, we maintain that urban poor women face barriers to access of formal obstetric services at family, community, and health facility levels, and efforts to reduce maternal morbidity and mortality among the urban poor must tackle the barriers, which operate at these different levels to hinder women's access to formal obstetric care services. We recommend continuous community education on symptoms of complications related to pregnancy and timely referral. A focus on training of health personnel on "public relations" could also restore confidence in the health-care system with this populace. Further, we recommend improving the health facilities in the slums, improving the services provided by TBAs through capacity building as well as involving TBAs in referral processes to make access to services timely. Measures can also be put in place to enhance security in the slums at night.