Maternal health services continue to favour the wealthiest in lower and middle income countries. Debate about the potential of performance-based financing (PBF) to address these disparities continues. As PBF is adopted by countries, it is critical to understand the equity effects for maternal services. The aim of this study is to examine the effects of PBF on equity in maternal health service use when no specific provisions target the poorest in the population. In Rwanda, PBF was designed to increase health service use, which was universally low. Paired districts were randomly assigned to intervention and control for PBF implementation. Using Rwanda's Demographic Health Survey data from 2005 (pre-intervention) and 2007-8 (post-intervention), a cluster-level panel dataset of 7899 women 15-49 years of age from intervention (4477) and control districts (3422) was created. The impact of PBF on reported use of facility deliveries, antenatal care (ANC) and modern contraceptive use was estimated using a difference-in-differences model with community fixed effects. Interaction terms between wealth quintiles and PBF were estimated to identify the differential effect of PBF among poorer women. The probability of a facility delivery increased by 10 percentage points in the intervention when compared with the control districts (P = 0.014), while no significant effects were noted for ANC visits or modern contraceptive use. Service use increased for intervention and control populations and across all wealth quintiles from 2005 to 2007, with no evidence that PBF was a pro-poor or a pro-rich strategy. Insurance remained a positive predictor of service use. This research suggests that if service use is uniformly low then a PBF programme that incentivizes select services, such as facility deliveries, may improve service use overall. However, if the equity gap is extreme, then a PBF programme without equity targets will do little to alleviate disparities.