Objective: Cardiovascular disease is highly prevalent in the chronic kidney disease population. The aim of the present study was to assess data from 24 h ambulatory blood pressure (BP) monitoring and 24 h pulse wave analysis (PWA) in dialyzed children and investigate their association with left ventricular mass as a marker of increased cardiovascular risk. Design and method: Children and adolescents aged 6 to 18 years, on dialysis for more than 12 months, [16 on peritoneal dialysis (PD) and 12 on hemodialysis (HD)], underwent 24 h ambulatory BP monitoring, 24 h PWA, and echocardiography. The population represents the whole pediatric dialysis cohort in Greece for the years 2019-2020. Results: Left ventricular mass index (LVMI) levels and prevalence of left ventricular hypertrophy (LVH) were similar between PD and HD patients. Peripheral and central BPs, and pulse wave velocity (PWV) values were also similar between PD and HD patients. However, HD patients presented significantly higher augmentation index (AIx75) (30.54 ± 6.14 vs 22.10 ± 9.96 %, p < 0.05), cardiac index (CI) (4.35 ± 0.90 vs 3.35 ± 0.54 l/m2, p < 0.005) and heart rate (94.20 ± 9.39 vs 84.92 ± 12.61 beats/min, p < 0.05) compared to the PD patients. Mean arterial pressure (MAP) z score (R2 = 0.34, P < 0.005), SBP/DBP dip (R2 = 0.21 and R20.22, respectively, P < 0.05), central systolic BP (cSBP) z score (R2 = 0.39, P < 0.001), PWV (R2 = 0.26, P = 0.005), CI, (R2 = 0.14, P < 0.05), AIx (R2 = 0.26, P = 0.005) associated with LVMI. Among laboratory parameters only Hb levels associated with LVMI. In stepwise linear regression with dependent variable LVMI and covariates Hb, MAP, SBP/DBP dip, cSBP, PWV, CI, AIx, the parameter that independently associated with LVMI levels was cSBP (B = 2.68, 95%CI 1.45–3.91, p < 0.001). All children with LVH in the PD group and 50% with left ventricular hypertrophy in the HD group had high cSBP (>95th pc). Conclusions: cSBP is the major determinant of LVMI levels in children on dialysis. Performing PWA seems to have an important role on the assessment of CV risk in children on dialysis.