CVD and cancer are the leading causes of mortality globally. Accumulating evidence suggests that cancer patients have a significantly increased risk of cardiovascular disease. Emerging evidence suggests a bidirectional link between these diseases, possibly mediated by hormonal changes, but further research needs to be performed to explore the specific role of hormone level changes in both diseases. We conducted a two-sample Mendelian randomization (MR) analysis using GWAS summary statistics from multiple cohorts of prostate cancer, ER+ breast cancer, and coronary atherosclerosis. MR analyses (IVW, MR-Egger, WM) demonstrated a significant causal relationship between both prostate and ER+ breast cancer and increased risk of coronary atherosclerosis. Hormone-related genitourinary tumors may contribute to the development of coronary atherosclerosis. This study is the first to provide causal evidence for such associations using MR.