Objective To assess the causal relationships between 91 inflammatory proteins and 5 cardiovascular diseases (including aortic dissection, aneurysm, coronary heart disease, non-rheumatic valve disease, and rheumatic valve disease) by Mendelian randomization (MR) and reverse MR. Methods MR and reverse MR analyses were used to assess bidirectional causality between 91 inflammatory proteins and 5 cardiovascular diseases based on Genome-Wide Association Studies (GWAS) data from European populations. MR analysis methods involved inverse variance weighted, weighted median, MR-Egger, simple mode and weighted mode approaches. Sensitivity analysis methods included Cochran’s Q test, MR-Egger intercept test, MR-PRESSO method, and leave-one-out approach. Results A total of 16 inflammatory proteins might be associated with the risk of cardiovascular diseases, including C-C motif chemokine ligand (CCL)20, CD5, CCL28, interleukin 20 receptor α (IL-20RA), latency-associated peptide transforming growth factor β1 (LAP-TGF-β1), thymic stromal lymphopoietin (TSLP), cystatin D (CST5), leukemia inhibitory factor (LIF), eukaryotic translation initiation factor 4E binding protein 1 (EIF4EBP1), CCL4, interleukin 22 receptor α1 (IL-22RA1), interleukin (IL)-10, IL-17C, monocyte chemoattractant protein (MCP)-2/CCL8, neurturin (NRTN), and MCP-3/CCL7. Furthermore, the progression of cardiovascular diseases might potentially lead to changes in the levels of 10 inflammatory proteins, including CCL11, IL-8, tumor necrosis factor β (TNF-β), fibroblast growth factor (FGF)-19, interleukin 10 receptor α (IL-10RA), FGF-21, interleukin 10 receptor β (IL-10RB), β-nerve growth factor (β-NGF), CD5, and MCP-1/CCL2. Conclusion The present study highlights the bidirectional causal relationship between an array of inflammatory proteins and the 5 cardiovascular diseases. Further research on the correlation between various inflammatory proteins and the above cardiovascular diseases has potential clinical value.