Background In the past decade, the prevalence of diabetes has grown more rapidly in low- and middle-income countries than in high-income countries. In 2019, Ethiopia is the fourth highest contributor to cases with diabetes in Africa with 1.7 million total cases. The present study was aimed to determine the prevalence of abnormal glucose metabolism and associated factors in Mekelle city, Northern Ethiopia. Methods and Materials Community-based cross-sectional study was conducted among 321 randomly selected participants aged 20 years and above. Sociodemographic, lifestyle, clinical, and anthropometric data were collected in accordance with the STEPwise approach as recommended by the World Health Organization (WHO) for non-communicable disease (NCDs) surveillance. Blood glucose and lipid profiles were determined using a fasting venous blood sample. Bivariate and multivariable logistic regression analysis was used to identify factors associated with abnormal glucose metabolism. The level of statistical significance was set at p ≤0.05. Results More than half (54.8%) of the participants were women with an overall mean (±SD) age of 39.0 (±14.2) years. The overall prevalence of pre-diabetes and diabetes was 12.5% and 9.3%, respectively, with a mean (±SD) fasting blood glucose of 97.42 (±38.03) mg/dL. More than two-thirds (70.0%) of adults with diabetes were not aware of being diabetes. Advanced age, hypercholesterolemia, medium and high rank of heart rate, and raised waist to height ratio were significantly associated with a higher risk of pre-diabetes, whereas having house servant, systolic hypertension, and hypercholesterolemia were significantly associated with diabetes. Conclusion We found a high prevalence of prediabetes and diabetes with more than two-thirds (70.0%) of newly diagnosed adults with diabetes, which showed a lack of awareness in the community. Awareness creation together with access to basic diagnostics in the primary health-care settings should therefore be a top priority to prevent its progression and complication.