The prognostic importances of on-treatment clinic and ambulatory blood pressure (BP) levels have never been investigated in individuals with resistant hypertension. We aimed to evaluate them for the occurrence of incident cardiovascular and mortality outcomes in a prospective cohort of 1726 patients with resistant hypertension. Clinic and ambulatory BPs were measured at baseline and serially during follow-up (analyzed as time-varying and as mean cumulative BPs) and also categorized as controlled/uncontrolled as defined by the traditional and new 2017 American College of Cardiology/American Heart Association criteria. Multivariate Cox analyses examined the associations between BP parameters and the occurrence of total cardiovascular events, major adverse cardiovascular events, and cardiovascular and all-cause mortalities. C statistics and the integrated discrimination improvement indexes evaluated the improvement in risk discrimination. Over a median follow-up of 8.3 years, 417 total cardiovascular events occurred (358 major adverse cardiovascular events) and 391 individuals died (233 cardiovascular deaths). All single systolic BP (SBP) parameters significantly predicted all outcomes, but the associations were stronger for ambulatory SBPs than for clinic SBPs and for on-treatment SBPs (particularly for mean cumulative) than for baseline SBPs, and both improved risk discrimination (with increases in C statistic of up to 0.021 and integrated discrimination improvements of up to 19.7%). These findings were consistent for diastolic BPs. Uncontrolled ambulatory BPs were associated with higher risks for all outcomes, whereas uncontrolled clinic BPs were not. In conclusion, mean cumulative ambulatory BPs during follow-up were the best prognostic markers of adverse cardiovascular outcomes and mortality in patients with resistant hypertension. Serial ambulatory BP monitoring shall be more widely used in resistant hypertension management.