The goal of improving the health status of people living in developing countries has received increasing priority in recent years. To achieve this goal, evidence is needed regarding methods for optimal allocation of expenditure within particular program areas. Among several competing programs, a commitment has been made to improve maternal health as part of the Millennium Development Goal targets. While there is a growing body of cost-effectiveness evidence relating to maternal healthcare programs, underutilization of services is still pervasive, especially among poorer groups of the population. A major reason for such underutilization lies in underlying adverse socioeconomic factors, or barriers, which impede healthcare use. This article reviews the evidence from studies that have conducted multivariate analyses to quantify the effects of education, economic status and distance barriers on service use. It is concluded that it is not possible to state categorically whether one particular barrier is more important than others and that efforts should continue to consider demand-side barriers more fully, along with supply-side barriers.