Increased vascular stiffness is an established risk marker of cardiovascular diseases (CVD) in adults with end-stage renal disease, but its role in pediatric patients remains to be defined. We prospectively examined arterial compliances of adolescents and young adults on hemodialysis (HD) using diastolic pulse wave analysis (DPWA). Each of the ten HD patients (age 17.3 +/- 3.9 years; mean +/- SD) had two DPWA tests within a three-week time period. DPWA measurement was performed before and hourly until the end of three-hour HD. Pre-HD large artery elasticity index (LAEI) was reduced in one patient and small artery elasticity index (SAEI) was reduced in another. Neither patient was hypertensive. Eight other patients had a reduction in both LAEI and SAEI. Among them, six patients had systolic and/or diastolic hypertension, and the other two were normotensive. Serum phosphorus correlated positively with stroke volume and cardiac output indices and negatively with SAEI. The reduction in BP during HD correlated with the amount of fluid removal. LAEI and SAEI were unchanged during HD. In conclusion, the reduction in LAEI and/or SAEI was observed in four normotensive patients, suggesting hypertension was not the only contributing factor for the reduced arterial compliances in our patients. The association between SAEI and serum phosphorus suggests that SAEI derived from DPWA can potentially be an early non-invasive, operator-independent, and volume-independent marker of CVD in adolescents and young adults receiving HD. Longitudinal studies with a larger sample size are needed to confirm our observation and speculation.