Background: Catestatin is an important peptide in the pathophysiology of chronic inflammatory conditions. Patients with inflammatory bowel diseases (IBD) have an increased cardiovascular (CV) risk compared to the general population, despite the lower prevalence of typical CV disease risks. In IBD, there is a lack of clinical studies related to catestatin, as well as analyzes of arterial stiffness parameters in relation to catestatin levels. Aims of the study: The main objectives of this study were to determine the potential difference in the level of catestatin and indicators of arterial wall elasticity between patients with inflammatory bowel diseases compared to the control group of subjects. The secondary objectives of the study were to examine whether there is a difference in catestatin levels and arterial wall elasticity parameters between groups of subjects with ulcerative colitis (UC) and Crohn's disease (CD), and between subjects on biological therapy and those treated with other therapy. Also, as secondary goals, were to examine whether there is a connection between catestatin levels and certain anthropometric, clinical, and laboratory parameters of inflammatory bowel disease activity and with indicators of the elasticity of the arterial wall. Participants and Methods: A total of 80 IBD subjects were included (of which 45 subjects with Crohn's disease and 35 subjects with ulcerative colitis) and 75 healthy control subjects, after applying predefined inclusion and exclusion criteria. Anamnesis was taken from all patients, a physical examination was performed with anthropometric measurements and blood was sampled for laboratory analysis. The serum concentration of catestatin (Phoenix Pharmaceuticals Inc., Burlingame, CA, USA) was determined by a double enzyme-linked immunosorbent assay (ELISA) according to the manufacturer's instructions. Applanation tonometry (AT), a non-invasive method for determining pulse wave velocity (PWV), which has a strong correlation with invasive methods, was used to assess arterial stiffness. Assessment of disease activity in subjects with IBD was performed by two experienced gastroenterology specialists who assessed disease activity parameters independently. Standard clinical and endoscopic collections were used. Results: Catestatin levels were in significantly positive corelation in subjects with IBD compared to control subjects (11.29 ± 9.14 vs. 7.13 ± 6.08 ng/mL; p = 0.001). Subjects with UC had a statistically significant higher level of catestatin compared to CD subjects (13.50 ± 9.58 vs. 9.03 ± 6.92 ng/mL; p = 0.021), this corelation remained significant after ANCOVA analysis. Subjects with IBD had statistically significant higher values of cAIx (16.36 ± 9.95 vs. 10.31 ± 8.19 %; p < 0.001), cAIx-75 (14.88 ± 10.59 vs. 6.87 ± 9.50 %; p < 0.001), PWV (8.06 ± 3.23 vs. 6.43 ± 1.47 m/s; p < 0.001) and pulse frequency (72.04 ± 12.21 vs. 68.13 ± 9.14 beats/min; p = 0.027) compared to the control group of subjects, the difference in the mentioned parameters of arterial stiffness among the studied groups persisted even after adjustments for age and BMI (p < 0.05). The IBD group had statistically significant more subjects with target organ damage, defined as PWV>10 m/s (17.5%, N=14 vs. 2.7%, N=1; p = 0.002), and the group of subjects with positive PWV criteria for target organ damage (PWV>10 m/s) had a statistically significant higher catestatin level (20.7-23 vs. 7.4-11 ng/mL; p = 0.001). Multiple linear regression analysis determined that PWV is an independent predictor of catestatin level (β = 1.20; p < 0.001). Binomial logistic regression found that catestatin (1.089 (1.022-1.161), p = 0.009), PWV (1.515 (1.166-1968), p = 0.002) and cAIx-75 (1.060 (1.024-1.097), p = 0.001) statistically significant predictors of positive IBD status. Conclusions: Subjects with IBD have a statistically significant higher level of catestatin and greater arterial stiffness compared to healthy subjects. Catestatin and pulse wave velocity have been shown to be independent predictors of the presence of inflammatory bowel disease. Elevated catestatin and pulse wave velocity in subjects with inflammatory bowel disease could indicate an increased cardiovascular risk in this population, independent of classical risk factors for cardiovascular disease. Finally, new preclinical and translational studies are needed in the future to investigate the complex pathophysiology of cardiovascular diseases in inflammatory bowel diseases.