Hypertension represents a key risk factor for mortality in chronic kidney disease (CKD). This study evaluated associations of ambulatory blood pressure (BP) with total and cardiovascular mortality in patients according to kidney function. From the Spanish ABPM Registry, we included 34,006 hypertensive patients with available estimated glomerular filtration rate (eGFR), recruited from 2004 to 2014 (median follow-up of 9.7 years). Hazard ratios (HR) from fully-adjusted Cox models were used for associations between BP and all-cause and cardiovascular mortality in subgroups depending on normal or reduced eGFR. Different cutoffs for ambulatory systolic BP and the risk of mortality were also assessed. A total of 4408 patients (13.0%) had an eGFR <60 mL/min/1.73 m2, and 1457 (33.0%) died during follow-up. 24-h systolic BP (HR 1.25 per 1-SD increment, 95% CI 1.20-1.31), daytime systolic BP (1.21; 1.15-1.26), and nighttime systolic BP (1.30; 1.25-1.36) were associated with total mortality, whilst the association with office SBP was U-shaped. A 24-h systolic BP < 120 mmHg was associated with reduced rates of mortality only in patients with impaired kidney function. Similar results were observed for the associations with cardiovascular mortality. We conclude that ambulatory BP was more informative about the risks of death than clinic BP in patients with impaired kidney function. Lower risks of mortality were related to lower levels of ambulatory BP in patients with impaired kidney function.