Background Exclusive breastfeeding (EBF) for the first 6 months of life is essential for maternal and child health. Breast milk is considered the most suitable food for the child in early years of life. Studies carried out in Cape Verde (INE; MSSS, Apresentação dos Principais Resultados Preliminares do IDSR-III, 2018) showed prevalence of EBF below the values recommended by the (WHO & UNICEF, Global Breastfeeding Scorecard, 2018. Enabling Women To Breastfeed Through Better Policies And Programmes, 2019). However, the determinants of EBF across the country have never been identified. The objective of this study is to estimate prevalence and identify the determinants of EBF in Cape Verde. Methods This is a quantitative, descriptive and cross-sectional study carried out between July 2018 and March 2019. The study population consisted of 1717 mothers of children aged less than or equal to 2 years, users of the Health Centers of the islands of Santo Antão, S. Vicente, Sal, Santiago and Fogo. A structured questionnaire was applied to mothers through an interview. The prevalence of exclusive breastfeeding was estimated by frequency analysis. The chi-square test was used to assess the association between the duration of EB and the variables maternity leave, mother’s education, family income and health care variables. In order to identify the determinants of EBF, a binary logistic regression analysis was used. Results At the time of data collection, 32.50% of mothers practiced EBF. The present study shows that exclusive breastfeeding is influenced by several factors. The most representatives are maternal age (OR = 0.001*), level of education (OR = 0.028*), parity (OR = 0.004*) and number of prenatal consultations (OR = 0.019*). Receiving breastfeeding counseling was the only health care variable that was associated with the duration of EBF (p = 0.029). Conclusion In Cape Verde, the prevalence of EBF can be considered reasonable. The present study shows that EBF in the country is influenced by maternal age, level of education, parity and number of prenatal consultations.