Objective This study examined the relationship between cognitive impairment status and all‐cause mortality among the oldest‐old Chinese. Methods A total of 7474 survey participants 80 years of age and above came from the Chinese Longitudinal Healthy Longevity Survey 1998–2012 waves. Baseline cognitive impairment status was assessed using the Chinese version of the mini‐mental state examination (MMSE), with total score ranging from 0 to 30. Cox proportional hazards regressions were performed to examine the relationship between baseline cognitive impairment status in 1998 and subsequent all‐cause mortality during 1998–2012, adjusting for various individual characteristics at baseline. Results Compared with those with no or mild cognitive impairment (18 ≤ MMSE score ≤ 30) at baseline, participants with moderate‐to‐severe cognitive impairment (0 ≤ MMSE score ≤ 17) were 28% (95% confidence interval = 20%, 37%) more likely to die during the follow‐up period from 1998 to 2012. A dose–response relationship between baseline severity level of cognitive impairment and mortality was evident. Compared with those without cognitive impairment (25 ≤ MMSE score ≤ 30) at baseline, those having mild cognitive impairment (18 ≤ MMSE score ≤ 24), moderate cognitive impairment (10 ≤ MMSE score ≤ 17), and severe cognitive impairment (0 ≤ MMSE score ≤ 9), were 20% (13%, 28%), 38% (27%, 51%), and 47% (33%, 62%) more likely to die during the follow‐up period. No statistically significant gender differences in the relationship between cognitive impairment status and mortality were found. Conclusion Baseline cognitive impairment was inversely associated with longevity among the oldest‐old Chinese. Copyright © 2016 John Wiley & Sons, Ltd.