Introduction: Cognitive impairment is a major cause of dependency in older people. The aim of this study was to identify factors associated with severe cognitive decline, as assessed by the mini-mental state examination (MMSE), in communitydwelling adults aged 55+ in Cameroon. Method: Data are from a cross-sectional survey carried out in Cameroon. The cognitive status was assessed using the MMSE and a score of 18/ 30 or lower is considered as a proxy of severe cognitive decline. Result: A total of 403 adults participated in the study. Of these, 16 (3.9%) had an MMSE score <18 and were considered to have cognitive impairment. The rate of severe cognitive decline increased with rising age, from 2.1% in those aged 55-64 years, to 3.3% in those aged 65-74, and 11% in those aged 75 and older. The factors associated with cognitive impairment (MMSE score <18) by multivariate analysis in our population are level of education (OR 0.10 [95% CI: 0.02-0.37], p < 0.01), body mass index (BMI) (OR 0.88 [95% CI: 0.78-0.99], p = 0.03), and IADL score (OR 0.12 [95% CI: 0.03-0.38], p < 0.001). Conclusion: The three main factors associated with cognitive impairment were education, IADL (Instrumental Activity of Daily Living) dependency, and BMI. This study shows that among older people in sub-Saharan Africa, the effect of BMI, IADL dependency, and education on cognitive function appears similar to that observed in middle-and high-income countries.