Background: Electrolyte abnormalities are common metabolic disturbances among patients with type 2 diabetes mellitus (T2DM). Hyperglycemia, osmotic diuresis, altered insulin action, gastrointestinal losses, renal dysfunction and medications may contribute to disturbances in sodium, potassium, chloride and bicarbonate concentrations. Despite their potential clinical significance, routine assessment of serum electrolytes may receive inadequate attention, particularly in resource-limited settings. Objective: To determine the prevalence and pattern of serum electrolyte imbalance among patients with T2DM in North-Eastern Nigeria. Methods: This descriptive cross-sectional study was conducted at the Chemical Pathology Department of a tertiary hospital in North-Eastern Nigeria between January and June 2025. One hundred (100) confirmed T2DM patients and fifty (50) apparently healthy non-diabetic controls were recruited. Serum sodium, potassium and chloride were measured using ion-selective electrode methods, while bicarbonate was measured by an enzymatic method. Data were analysed using SPSS version 25.0 and presented as mean ± standard deviation and percentages. Results: The mean age of participants was 54.2 ± 10.1 years. Among T2DM patients, 58% were male and 42% were female. The mean duration of diabetes was 6.8 ± 4.2 years. At least one electrolyte abnormality was present in 68% of T2DM patients. Hyponatremia was the commonest abnormality (22%), followed by hypokalaemia (18%), hypochloraemia (15%), hyperkalaemia (8%) and hypernatremia (5%). Mean serum Na+, K+, Cl− and HCO3− were lower in T2DM patients than controls: 132.5 ± 4.2 vs 138.4 ± 2.8 mmol/L; 3.6 ± 0.5 vs 4.2 ± 0.4 mmol/L; 99.2 ± 3.8 vs 104.5 ± 2.9 mmol/L; and 22.1 ± 2.1 vs 24.8 ± 1.8 mmol/L, respectively. Conclusion: Electrolyte imbalance was common among T2DM patients in this study, with hyponatraemia and hypokalaemia being the predominant abnormalities. Routine electrolyte monitoring should be considered as pa