Aims: The aim of the present study was to determine the prevalence of diabetes, and to assess its awareness and related risk factors among adult Guineans.Methods: A population-based cross-sectional survey was conducted on 1 100 adults (46.6% women) aged 35–64 years from Lower Guinea, during September to December 2009, using the WHO STEPwise approach of surveillance of chronic disease risk factors. Data were collected in three steps: demographic and behavioural risk factors, blood pressure and anthropometric measurements, and fasting blood cholesterol and glucose testing. A multi-stage cluster sample design was applied to generate nationwide representative data.Results: The mean age of all participants was 47.3 years (SD 8.8), similarly in Conakry, rural Lower Guinea and urban Lower Guinea. The prevalence of diabetes was 5.7% (95% CI 4.0–8.1). Among participants with diabetes, only 44.0% were aware of their status. In multivariable logistic regression analysis, determinants of diabetes prevalence were urban residency, male sex, age group 45–64 years, increased waist circumference, hypertension and hypercholesterolemia. Male sex, rural residency, age group 45–54 years, no formal education, waist circumference, hypertension and hypercholesterolemia were independent predictors of screen-detected diabetes.Conclusion: The present study found a high prevalence and low awareness of diabetes, suggesting the need for appropriate actions to strengthen primary healthcare approaches towards non-communicable diseases in Guinea.Keywords: Diabetes, epidemiology, Guine