BackgroundWith a fertility rate of 5.5 children per woman, Burundi has been ranked as fourth highest country with the highest fertility rate in the world. Family planning is known to allow couples to achieve the desired family size, appropriate space birth and the limitation of pregnancies. Also, family planning can contribute to mitigating some health issues such as unintended pregnancies and abortions all of which, are often associated with multi-parity. In conservative community in rural Burundi, knowledge on family planning is high and such services are free yet utilisation is low. Employing a mixed methods, this study first quantifies contraceptive prevalence and second, explore the contextual multilevel factors associated with low family planning utilisation MethodsAn explanatory sequential mixed study was conducted. Five hundred and thirty women in union were interviewed using structured and pre-tested questionnaire. Next, 11 focus group discussions were held with community members (n=132). The study was conducted in eighteen collines of two health districts of Vyanda and Rumonge in provinces of Bururi and Rumonge respectively. Quantitative data was analysed with SPSS and qualitative data was coded and deductive thematic methods were applied to find themes and codes.ResultsThe overall contraceptive prevalence was 22.6%. Injectables (40%), Implants (24.6%), Male condom (10.8%) and pills (6.2%) were the major contraceptive methods utilized by study participants. Natural contraceptive methods were used by 13.8% of women interviewed. The reasons for not using modern contraceptive methods were side effects (51%), perceived postpartum (18.8%), religious beliefs (12.9%), partner’s opposition (8.4%), partner absenteeism (6.4%) and lack of awareness (2.5%). The qualitative component identified fear of side effects, religious beliefs, cultural barriers, spousal communication gap and refusal of family planning services by health practitioners as factors.ConclusionThe study suggests that low uptake of family planning can be attributed to perceived or experienced side effects as well as deeply rooted negative beliefs which are reinforced by religious beliefs. Men and religious leaders’ involvement in family planning initiatives can positively impact behaviour change and increase family planning acceptance.