While observational studies suggest a connection between skipping breakfast and myocardial infarction (MI), the causal nature of this relationship is unclear. This study aims to investigate the genetic causal relationships between breakfast skipping and MI through Mendelian randomization (MR). Employing genetic data from a public genome-wide association study, this research focuses on genetic variations linked to breakfast skipping and MI. The primary analytical method was the inverse variance-weighted approach, complemented by additional methods like MR-Egger, weighted median, and mode analyses. It also includes heterogeneity and horizontal pleiotropy tests such as the Cochrane Q test, MR-Egger intercept, and MR-PRESSO tests, with a leave-one-out analysis for enhanced sensitivity assessment reliability. The study discovered a notable association between breakfast skipping and an increased risk of MI (odds ratios: 1.34, 95% confidence intervals: 1.03-1.76, P = .027). The test revealed no heterogeneity or multiplicity, and the sensitivity analysis confirmed the robustness of the results. Our MR analysis suggests that habitual breakfast skipping might elevate the likelihood of MI, underlining the importance of regular breakfast consumption in potentially mitigating heart attack risks.