Scaling-up of skilled attendants and facility-based services is necessary for improving maternal and child care in developing countries but their effectiveness is crucially influenced by the uptake of such services. This study set out to establish the pattern and uptake of maternity services and associated factors against the backdrop of rapid urbanization in Nigeria. A cross-sectional study of socio-demographic and obstetric characteristics of mothers attending the Bacille Calmette-Guérin (BCG) immunization clinics in inner-city Lagos was conducted from July 2005 to December 2007, and their association with non-hospital delivery and use of unskilled attendants was determined by multiple logistic regression analyses. Of the 6465 participants, over half (51.4%) delivered outside hospital facilities and 81.8% of this group had no skilled attendants at delivery. Non-hospital delivery or the presence of unskilled attendants at delivery was associated with teenage mothers, Muslim religion, low or middle social class and use of herbal drugs in pregnancy. Additionally, non-hospital delivery was associated with ethnicity (Yoruba tribe), lack of tertiary education or full-time employment, accommodation with shared sanitation facilities and multiparity. The results suggest that availability of and access/proximity to hospital facilities or skilled attendants is no guarantee of uptake of maternity services. Efforts aimed at improving maternal and child health in developing countries should take cognisance of the socio-demographic and cultural underpinnings of maternal health-seeking behaviour of urban mothers beyond the provision of facility-based services or strengthening of the existing health care systems.