Context Longitudinal patterns of resting heart rate (RHR) in patients with diabetes mellitus and their association with health outcomes are not well-characterized. Objective We sought to explore the RHR trajectories in patients with diabetes mellitus and their association with cardiovascular disease (CVD) and all-cause mortality. Design The Kailuan Study is a prospective cohort study. Participants underwent health examinations biennially starting in 2006 and were followed until December 31, 2020. Setting General community. Participants A total of 8218 diabetic participants who attended at least 3 of the examinations conducted in 2006, 2008, 2010, and 2012 were included. Main outcome measures CVD and all-cause mortality. Results We identified 4 RHR trajectories in participants with diabetes mellitus between 2006 and 2012: low-stable (range, 66.83-64.91 beats/min; n = 1705), moderate-stable (range, 76.30-76.95 beats/min; n = 5437), high-decreasing (mean decreased from 92.14 to 85.60 beats/min; n = 862), and high-increasing (mean increased from 84.03 to 111.62 beats/min; n = 214). During an average follow-up of 7.25 years, 977 cases of CVD and 1162 deaths were identified. Compared with the low-stable trajectory, adjusted hazard ratios (HRs) for CVD were 1.48 (95% CI, 1.02-2.14; P = .04) for the high-increasing trajectory, adjusted HRs for all-cause mortality were 1.34 (95% CI, 1.14-1.58; P < .01) for the moderate-stable trajectory, 1.68 (95% CI, 1.35-2.10; P < .01) for the high-decreasing trajectory, and 2.47 (95% CI, 1.85-3.31; P < .01) for the high-increasing trajectory. Conclusions RHR trajectories were associated with the subsequent risks of CVD and all-cause mortality in patients with diabetes mellitus.