OBJECTIVE To examine how socioeconomic differences are related to the prevalence, awareness and treatment of diabetes in rural Yunnan province, a relatively undeveloped province in southwest China. METHODS A cross-sectional survey was conducted from 2008 to 2010; 10 007 consenting individuals aged >= 18 years were selected to participate in the study using a stratified, multistage sampling technique. Information about participants' demographic characteristics, smoking habits, drinking habits, awareness and treatment of diabetes, and family history of diabetes were obtained using a standard questionnaire. Height, weight, waist circumference, hip circumference, fasting blood sugar level and blood pressure were also measured for each individual. Data were analysed using multivariate logistic regression. RESULTS The age-standardised presence of diabetes was 6.8% in the study population. In diabetic subjects, 28.7% were aware that they had diabetes, and 22.6% had received treatment. After controlling for age, sex, smoking behaviour, drinking behaviour, hypertension, being overweight, central obesity and family history of diabetes, individual educational level was negatively associated with the prevalence of diabetes and positively associated with the awareness and treatment of diabetes. The awareness and treatment of diabetes showed a negative relationship with ethnic minority status and a positive relationship with individual household income. CONCLUSIONS There are low levels of awareness and treatment among individuals living with diabetes in rural southwest China. Strategies that can enhance public awareness of diabetes and increase access to affordable medications are urgently needed, especially for poor, less educated individuals who belong to ethnic minorities.