Objective: To explore the causal relationsh ip between household income and breastfeeding by applying Mendelian Randomization (MR) analysis. Methods: We obtained data on household income and breastfeeding practices from the IEU Open GWAS database derived from European populations. The causal relationship between household income and breastfeeding was analyzed by five methods: Inverse Variance Weighted (IVW), MR Egger regression, weighted median, weighted, and simple models. Cochran’s Q test and MR Egger regression were performed to analyze heterogeneity and horizontal pleiotropy, respectively. Results: IVW associated higher household income with an increased rate of breastfeeding (OR = 1.05, P = 4.05e-05). This finding was corroborated by weighted median (OR = 1.06, P = 5.5e-04) and simple (OR = 1.09, P = 0.02) models. Reverse analysis showed that breastfeeding did not increase family income (P > 0.05). Quality control analyses indicated the absence of heterogeneity and pleiotropy. Conclusion: Our study disclosed a positive causal relationship between household income and an increased rate of breastfeeding in Europeans. However, a causal relationship between breastfeeding and increased household income was not evident.