Undiagnosed type 2 diabetes mellitus constitutes a significant threat to the health of commercial taxi drivers, safety of the passengers and other road users. This study determines the prevalence of pre-diabetes and type 2 diabetes mellitus among commercial taxi drivers in Buffalo City Metropolitan Municipality (BCMM), Eastern Cape and examines the factors associated with type 2 diabetes mellitus.A cross-sectional survey of 403 commercial taxi drivers was undertaken using the World Health Organization (WHO) STEPwise approach. Anthropometric, blood pressure, and blood glucose measurements followed standard procedure. Diabetes status was determined using the fasting blood glucose (FBG) test. Diabetes was defined as a FBG ≥7.0mmol/L or self-reported history of diabetes or current diabetes medication use (treatment), while pre-diabetes was defined as a FBG of 5.6 to 6.9 mmol/L. Awareness of diabetes was defined as a self-reported history of diabetes.The mean age of the study participants was 43.3 ± 12.5years. Prevalence of pre-diabetes and diabetes were 17% (95% CI: 13.4–20.6) and 16% (95% CI: 12.4–19.6), respectively. Of those who had diabetes (n = 63), the majority were aware of their diabetes status (n = 43) and were on treatment (n = 30). In the unadjusted logistic regression, age, ever married, hypertension, obesity, and driving for more than 5 years were independently associated with diabetes. However, only age >35 (adjusted odds ratio [AOR]= 3.65, CI: 1.17–11.32), ever married (AOR= 3.26, CI: 1.52–6.99) and hypertension (AOR= 3.23, CI: 1.56–6.69) were associated with diabetes in the adjusted logistic regression model.The prevalence of diabetes among commercial taxi drivers in this study is high, almost twice the national prevalence of diabetes in South Africa. Periodic health screening among this sub-population group is important to bridge the gap of undiagnosed diabetes in South Africa.