Background:Limited epidemiological data on pre-diabetes and diabetes mellitus among public service workers, considered an at-risk population, may undermine the government’s efforts toward addressing the scourge of non-communicable diseases in Nigeria. This study aimed to address this gap by determining the prevalence of pre-diabetes and diabetes mellitus (DM), and to examine their correlates.Methods:We conducted a workplace cross-sectional survey of 4828 public service workers across 47 ministries, departments and agencies in Ondo State, Nigeria. An adapted World Health Organisation (WHO) STEPwise surveillance questionnaire was utilised to obtain relevant items of demographic factors, medical history and lifestyle behaviour. Height, weight, blood pressure and fasting blood sugar were measured according to standard protocols. Pre-diabetes and DM were defined as fasting blood glucose 5.6-6.9mmol/L and greater than or equal to 7.0mmol/L, respectively. We performed univariate and multivariate model analyses to determine the associated factors of pre-diabetes and DM.Results:Overall, 2299 men and 2529 women participated in the study. The mean age of the participants was 40.4 years (SD±9.7) and the age range was 19 to 76 years. The prevalence of pre-diabetes and DM was 11.7% (n=563) and 5.3% (n=254), respectively. Women had a higher prevalence of pre-diabetes than men did (12.5% versus 10.8%). In univariate analysis, the following factors were associated with pre-diabetes and DM; aging (p<0.0001), marital status (p<0.0001), lower level of education (p=0.008), body mass index (BMI) (p<0.0001) and hypertension (p<0.0001). In multivariate model analysis, after adjusting for confounding factors, age ≥45 years (OR=1.8, 95%CI 1.3-2.4), lower level of education (OR=1.7, 95%CI 1.2-2.4), hypertension (OR=2.0, 95%CI 1.5-2.6) and overweight/obesity (OR=2.2, 95%CI 1.6-3.0) were the independent and significant determinants of DM.Conclusion:We found a high prevalence of pre-diabetes and DM in the study population. Cardio-metabolic screening of public category workers might contribute significantly towards bridging the gap of undiagnosed DM in the study setting.