Background: Little is known about the characteristics of older adults with cognitive impairment in Macao. This study aimed to determine the prevalence of cognitive impairment and the quality of life (QOL) of older adults living in the community and nursing homes. Methods: A consecutive sample of 413 subjects (199 from the community; 214 from nursing homes) was recruited and interviewed using standardized instruments. Cognition was measured with the Repeatable Battery for the Assessment of Neuropsychological Status and QOL with the brief version of the World Health Organization Quality of Life instrument. Results: Altogether 87 subjects (21.0%) had cognitive impairment. On multivariate analyses, advanced age (P < 0.001, OR = 1.06, 95%CI: 1.03–1.1) and depressive symptoms (P = 0.03, OR = 1.07, 95%CI: 0.005–1.1) were positively associated with cognitive impairment. Married marital status (P = 0.01, OR = 0.3, 95%CI: 0.1–0.7) and higher education level (P < 0.001, OR = 0.1, 95%CI: 0.06–0.3) were negatively associated with cognitive impairment. After the confounders were controlled for, cognitive impairment was significantly associated with the lower psychological (F = 6.3, P = 0.01) and social relationship domains of QOL (F = 4.0, P = 0.04). Conclusion: Cognitive impairment was found to be common in community-dwelling and nursing home resident older adults in Macao. Given cognitive impairment's negative impact on QOL, appropriate strategies should be implemented to improve access to treatment in this population.