Résumé : Purpose and objectives Exclusive breastfeeding (EBF) is recommended for a period of 6 months. Belgium's breastfeeding rates are among the lowest in Europe. The objective of the study is to provide the prevalence of breastfeeding (BF) in maternity ward, measure the duration of the EBF and describe the determinants of these practices in the French-speaking community of Belgium (Wallonia). Method A two-stage cluster sampling was drawn from the population of children aged 18–24 months living in the area in 2015 (n = 562). Factors associated with exclusive breastfeeding (EBF) to maternity ward were identified by bivariate analysis and logistic regression and Cox's proportional hazards model was used to identify factors associated with the risk of discontinuation EBF. Results At maternity ward the prevalence of EBF was 68.6% (64.7–72.4) and the median duration of 3.0 months (0.03–9). At 3 and 6 months of age, 45.8% (41.1–50.5%) and 11.5% (8.9–14.2) of the children were exclusively breastfed. At the maternity unit, the most strongly associated factor with EBF was the partner's attitude. The lower durations of the EBF are associated with existence of difficulties in implementation of BF and unsupportive partner's attitude. Conclusions Difficulties in implementation of the BF impact rate and duration of the EBF. Many mothers are unaware of pain related to the initiation of the BF. Information for mothers and appropriate care by health providers could allow better BF rates.