To examine whether household income is causally related to cardiovascular diseases and investigate the potential reasons.Using 2-sample Mendelian randomization analyses, we obtained summary statistics from genome-wide association studies of household income and a range of cardiovascular diseases, biomarkers, and socioeconomic factors.Higher household income was causally associated with lower risks of coronary heart disease (odd ratio [OR] = 0.63; 95% CI: 0.49-0.79; P = 0.0001), myocardial infarction (OR = 0.64; 95% CI: 0.50-0.82; P = 0.0003), and hypertension (OR = 0.71; 95% CI: 0.58-0.88; P = 0.0015). With increasing household income, the cardiovascular biomarkers including triglycerides, C-reactive protein, body mass index, fasting glucose were decreased whereas telomere length and high-density lipoprotein cholesterol were increased. Besides, individuals with higher household income were less likely to smoke (β = -0.34; 95% CI: -0.47 to -0.21; P = 1.91×10-07), intake salt (β = -0.14; 95% CI: -0.21 to -0.07; P = 0.0001), or be exposed to air pollution (β = -0.10; 95% CI: -0.15 to -0.06; P = 8.81×10-06) or depression state (β = -0.03; 95% CI: -0.04 to -0.02; P = 5.16×10-07). They were more likely to take physical activity (β = 0.06; 95% CI: 0.02 to 010; P = 0.0016) and have long years of schooling (β = 0.70; 95% CI: 0.62 to 0.78; P = 5.32×10-67).Higher household income is causally associated with better socioeconomic factors and improved cardiovascular biomarkers, which translates into a reduced prevalence of cardiovascular diseases. Policies to improve income equality may result in a reduced burden of cardiovascular diseases.Copyright © 2024 Elsevier Inc. All rights reserved.