OBJECTIVES: In Burkina Faso, only 2.1% of women give birth by caesarean section (CS). To improve the use of maternal health services during pregnancy and childbirth, many interventions were implemented during the 2010s including performance-based financing (PBF) and a free maternal health care policy (the gratuité). The objective of this study is to evaluate the impact of a supply-side intervention (PBF) combined with a demand-side intervention (gratuité) on institutional CS rates in Burkina Faso. METHODS: We used routine health data from all the public health facilities in 21 districts (10 that implemented PBF and 11 that did not) from January 2013 to September 2017. We analysed CS rates as the proportion of CS performed out of all facility-based deliveries (FBD) that occurred in the district. We performed an interrupted time series (ITS) analysis to evaluate the impact of PBF alone and then in conjunction with the gratuité on institutional CS rates. RESULTS: CS rates in Burkina Faso increased slightly between January 2013 and September 2017 in all districts. After the introduction of PBF, the increase of CS rates was higher in intervention than in non-intervention districts. However, after the introduction of the gratuité, CS rates decreased in all districts, independently of the PBF intervention. CONCLUSION: In 2017, despite high FBD rates in Burkina Faso as well as the PBF intervention and the gratuité, less than 3% of women who gave birth in a health facility did so by CS. Our study shows that the positive PBF effects were not sustained in a context of user fee exemption.