INTRODUCTION: Vascular calcification (VC), with the mechanisms remaining unclear, is closely related with dialysis patients' cardiovascular mortality and all-cause mortality. Irisin is a newly identified myokine. This study aims to evaluate the serum irisin levels of peritoneal dialysis (PD) patients and their relationship with VC. METHODS: This cross-sectional study enrolled stable PD patients in Peking University Third Hospital who were followed for >6 months. We used plain X-ray films of abdomen to quantitatively evaluate VC of abdominal aorta. VC was evaluated by abdominal aortic calcification (AAC) scores, and PD patients were divided into the high AAC score group (AAC score ≥4) and the low AAC score group (AAC score <4). Demographic data and laboratory indexes were collected. Serum irisin concentrations were measured by enzyme-linked immunosorbent assay. RESULTS: A total of 102 PD patients were enrolled in this study, and 52 patients (51.0%) were found to have a high AAC score of ≥4. Age, diabetic mellitus proportion, pulse pressure, hypercalcemia (corrected calcium >2.54 mmol/L) rate, serum ultrasensitive C reactive protein, and AAC scores were significantly higher in the high AAC score group than those of the low AAC score group (p < 0.05). The high AAC score group had lower diastolic blood pressure, serum albumin, and serum carbon dioxide combining power compared with the low AAC score group (p < 0.05). Serum irisin levels of PD patients with a high AAC score were significantly lower than those of PD patients with a low AAC score (109.7 ± 13.1 ng/mL vs. 115.9 ± 10.1 ng/mL, p = 0.010). The multivariate logistic regression analyses showed that serum irisin, diabetic mellitus, serum ultrasensitive C reactive protein, and age were independent factors influencing the occurrence of VC in PD patients. CONCLUSION: Our results are the first to provide a clinical evidence of the association between serum irisin and abdominal aortic calcification in PD patients. Lower irisin levels, diabetic mellitus, higher serum ultrasensitive C reactive protein, and older age could be potential predictive factors for VC in PD patients.