BACKGROUND: Arterial stiffness (AS) can be used to predict future cardiovascular diseases. High lipoprotein(a) (Lp(a)) levels were independently correlated with cardiovascular (CV) morbidity and death in patients with chronic renal insufficiency. The cardio-ankle vascular index (CAVI) is a useful biomarker of arteriosclerotic disorders and has a close relationship with a variety of CV events. This study aimed to investigate the correlation between serum Lp(a) levels and AS in patients on peritoneal dialysis (PD) using the CAVI. METHODS: A total of 86 adult patients who were on regular PD for at least 3 months were recruited in this study. The CAVI values were determined using the waveform device (VaSera VS-1000). A CAVI value of 9.0 on either side was defined as high. Serum Lp(a) levels were measured by an enzyme-linked immunosorbent assay. RESULTS: Among these participants, 35 of 86 (40.7%) belonged to the high CAVI group. In contrast to those with a normal CAVI, PD recipients in the high CAVI group had higher serum levels of total cholesterol ( = 0.003), triglycerides ( = 0.044), C-reactive protein ( 0.001), and Lp(a) ( 0.001), whereas their albumin levels were significantly lower ( = 0.026). Based on multivariable logistic regression analysis, serum Lp(a) (odds ratio [OR] 1.025, 95% confidence interval [CI] 1.010-1.040, = 0.001), total cholesterol (OR 1.042, 95% CI 1.005-1.081, = 0.027), and C-reactive protein (each increase 0.1 mg/dL, OR 1.217, 95% CI 1.008-1.469, = 0.041) levels were found as the parameters that could independently predict AS in patients on PD. Further, using Spearman's correlation analysis, both the left and right CAVIs revealed a significantly positive correlation with log-transformed Lp(a) levels ( = 0.588, 0.001; = 0.639, 0.001, respectively). CONCLUSIONS: Serum Lp(a) levels were postulated to participate in the pathogenic processes of AS in adult patients undergoing PD.