The C-reactive protein to lymphocyte ratio (CLR) has demonstrated associations with conditions characterized by persistent, mild inflammation. Given the inflammatory component of type 2 diabetes (T2DM), our aim was to explore the relationship between CLR and T2DM. T2DM patients attending internal medicine outpatient clinics were categorized into two groups based on their glycosylated hemoglobin (HbA1c) levels: well-controlled (HbA1c < 7%) and poorly controlled (HbA1c ≥ 7%) T2DM groups. Healthy individuals undergoing routine check-ups served as the control group. CLR levels were compared among the well-controlled and poorly controlled diabetic groups and the control group. The CLR levels in the T2DM group (3.51 (0.03-21.78)) were significantly higher than those in the control group (0.65 (0.02-2.92)) (p < 0.001). CLR exhibited a sensitivity of 63.2% and a specificity of 97.3% in predicting T2DM. Patients with poorly controlled diabetes had a CLR value of 4.76 (0.06-21.78), whereas those with well-controlled diabetes had a CLR value of 2.53 (0.03-12.07) (p < 0.001). The sensitivity and specificity of CLR in identifying poor diabetic control were 41.2% and 86.1%, respectively. The elevated CLR levels observed in T2DM patients, particularly in those with poorly controlled diabetes, suggest that CLR could serve as a valuable additional diagnostic tool in monitoring the treatment progress of T2DM patients.