BACKGROUND: Obesity contributes to the burden of chronic diseases and it is a public health challenge. The rate of overweight and obesity in South Africa is dramatically on the increase and disturbingly high. This study aimed at determining the prevalence and predictors of overweight and obesity among adults in Eastern Cape Province of South Africa; which information is lacking. METHODOLOGY: This cross-sectional survey utilised the WHO STEPwise approach in collecting data on demographic and behavioural factors from 1077 adults attending the three largest out-patient clinics in the Buffalo City Metropolitan municipality, Eastern Cape. Height and weight were measured in accordance with standard procedure. Obesity and overweight were defined according to WHO criteria. We performed bivariate and multivariate (logistic regression) analyses to determine the significant predictors of obesity. RESULTS: The prevalence of overweight and obesity were 24% and 46%, respectively. The prevalence of obesity was higher among female (53.4%) compared to males (27.4%). Obesity was strongly associated with pre-diabetes (250/54.7%, RR=2, 95% CI 1.6-2.6, p=0.001), diabetes (145/59.4%, RR=2.1, 95%CI 1.6-2.9, p=0.001) and hypertension (276/56.2%, RR=2.4, 95%CI 1.9-3.1, p=0.0001). In the multivariate analysis, after adjusting for confounding factors, only age (AOR= 2.0, 95%CI= 1.3-3.0), sex (AOR= 3.8, 95%CI= 2.7-5.3), being married (AOR=2.3, 95%CI= 1.7-3.2), hypertension (AOR=2.0, 95%CI= 1.5-2.8), diabetes (AOR=1.4, 95%CI=1.0-2.0) and no cigarette smoking (AOR= 2.8, 95%CI= 1.7-4.5) were the independent and significant predictors of obesity among the participants. CONCLUSION: The prevalence of obesity was high and strongly associated with cardiovascular risk factors. Health policies targeting obesity and cardiovascular risk factors should be prioritised by the Eastern Cape and South African government in order to mitigate the burden of non-communicable diseases