The effect of unilateral nephrectomy on the cardiovascular risk profile of living kidney donors has not been prospectively studied. We performed an observational cohort study of 58 living donors to 6 months postdonation for changes in 24-hr ambulatory blood pressure profiles, renal function, urine protein excretion, body mass index, glucose tolerance, and fasting lipid profiles. The 24-hr systolic blood pressure average and night-day ratio were unchanged from pre- to postdonation (118.9+/-11 vs. 118.1+/-14 mm Hg, P=0.77; 0.87+/-0.07 vs. 0.87+/-0.09, P=0.68, respectively). Estimated glomerular filtration rate declined from 91.9+/-16 to 61.6+/-12 mL/min/1.73 m2 (P<0.0001). Protein excretion, body mass index, glucose, and lipids were unchanged. No significant differences were noted between dippers and nondippers either pre- or postdonation. In summary, living kidney donation in the short term is safe. We suggest further observation of individuals with lower glomerular filtration rate for possible increased cardiovascular risk factors in the future.