Motivation Hypertension and type 2 diabetes mellitus are common in the black population of South Africa. The literature also shows that elevated blood glucose concentrations can lead to an increase in blood pressure and a blunted decline in nocturnal blood pressure. Therefore, the motivation for this study was to determine if blood glucose may play a role regarding the blunted nocturnal decline in blood pressure in African and Caucasian men. Aim The aim of this study was to investigate the relationship between a blunted nocturnal decline in blood pressure and blood glucose in African and Caucasian men. Methodology A comparative population study was preformed that consisted of 202 school teachers (101 African and 101 Caucasian) between the ages of 25–60 years from the North West Province, South Africa. Subjects were excluded if their body temperature was elevated, had a dependence or abuse of psychotropic substances, were regular blood donors and/or vaccinated in the previous three months. Ambulatory systolic (SBP) and diastolic blood pressure (DBP) were measured. Blood samples from the antebrachial vein were collected in sodium fluoride tubes to determine the serum glucose level and glycosylated hemoglobin A1c (HbA1c) percentage. Estimated average glucose (eAG) was determined from the percentage HbA1c by means of a regression formula. Means and proportions were compared by standard t–test and the chi–square test, respectively. Pearson correlations were used to determine unadjusted associations and multiple regression analysis to determine adjusted associations between variables. Results and Conclusion African men had an elevated HbA1c (p