The aim of this study was to investigate the risk factors for cognitive impairment in older people with diabetes. This cross-sectional study included 2626 community-dwelling participants with diabetes aged ⩾55 years, living in Beijing, China. The participants were screened for risk factors, including smoking, obesity, hypertension, stroke, coronary heart disease, dyslipidemia, depression, apolipoprotein E (APOE) genotype, and low physical activity. Cognitive function was assessed with the scholarship-adjusted Mini-Mental State Examination (MMSE): MMSE ⩽17 for iliterate participants; MMSE ⩽20 for primary school graduates (⩾6 years of education); and MMSE ⩽24 for junior school graduates or above (⩾9 years of education). The prevalence of cognitive impairment in older people with diabetes was 9.90%. Multiple logistic regression analysis demonstrated that stroke [odds ratio (OR) = 1.71, 95% confidence interval (CI) = 1.20-2.43], less than 0.5 h exercise per day (OR = 1.89, 95% CI = 1.37-2.61), and depression (OR = 1.64, 95% CI = 1.06-2.54), but not smoking, obesity, hypertension, dyslipidemia, and coronary heart disease, were independent risks for cognitive impairment in older people with diabetes. In addition, being married (OR = 0.66, 95% CI = 0.47-0.93) and urban living (OR = 0.33, 95% CI = 0.22-0.48) could decrease the risk of cognitive impairment. Stroke, depression, and less than 0.5 h exercise per day were independent risks for cognitive impairment in older people with diabetes, whereas being married and urban living were protective.