Background: Performance Based Financing (PBF) has been widely adopted in low and middle income countries with the aim to boast their health system performance. However, very little is been known about the effects of PBF on the health information system (HIS). Objective: To evaluate the short term effects of PBF on the quantity and quality of immunization data in the Dschang Health District. Method: A cross-sectional time series study was carried out in 23 health facilities under PBF in the DHD. Our sample size was exhaustive with inclusion criteria, health facilities that have existed for at least three years (2017 to 2018 before PBF and 2019 with PBF), and have been vaccinating for this period of time and disposes all their vaccination data collection tools for this period of time. Our sample size was exhaustive. Sources of data included the vaccination registers, monthly activity report and the district health information system. Results: The enrolment of pentavalent1 had a decrease of 11,2% between 2017 to 2018 and 11,6% between 2018 and 2019. For pentavalent3, the number of enrolment had a decrease of 10,6% between 2017 to 2018 and 14,3% from 2018 to 2019. The timeliness of EPI data witnessed a 7,5% increase between 2017 and 2018, and a drop of 73,7% between 2018 and 2019. The completeness of EPI data for the DHD from 98% to 96,6% in 2018 to 99,2% in across the three years. Using the verification factor number of health facilities with consistent data ranges from 13% to 52% and 70% and 13% to 43,5% and 70% for 2017, 2018 and 2019 for pentavalent1 and pentavalent3 respectively. Health facilities with improved PBF score across 2019 increased from 12 to 15 with PBF score ≥ 75% between the First trimester and the fourth trimester with no major change in data indicators. Conclusion: the quality and precision of EPI data have improved most especially in 2019 across the years from 2017 to 2019 with PBF. However, timeliness remains relatively low and should be improved.