Aim: To assess the use of glycated haemoglobin (HbA1c) as an alternative to diagnose diabetes mellitus in a Northern Nigerian population. Method and Results: Cluster sampling was done to select four hundred (400) subjects from ten (10) communities after informed consent from each participant. Demographic variables were recorded and obesity indices measured from each subject. Oral glucose tolerance test and HbA1c measurements were subsequently carried out. Though the HbA1c criteria missed some of the subjects diagnosed by the OGTT criteria, Receiver Operating Characteristics (ROC) curve showed that HbA1c level of > 6.5% was highly specific and sensitive in diagnosing diabetes with a discriminant ability of 91.3% and a high Youden index of 0.83. Conclusion: Glycated haemoglobin may be suitable to diagnose diabetes mellitus in some persons.