Objective: Compare the influence of diabetes control treatment on serum lipoprotein (a) concentrations. Setting: Patients of know diabetics attending or admitted to GGS Medical College, Faridkot and Hospital. Design: In this context lipoprotein (a) concentrations were compared with normal control group, a group of diabetic patients with glycated hemoglobin (HbA1c) less than 8.20%, and a group of diabetic patients with HbA1c of 8.0% or higher. Patients: One hundred normal controls and 130 diabetic subjects (75 with insulin-dependent diabetes mellitus and 55 with noninsulin-dependent diabetes mellitus). Results: Sixty patients with HbA1c levels of 8.0% or higher had higher (25 mg/dL) median levels of lipoprotein (a) when compared with either 100 normal controls (8.8 mg/dL) or 55 diabetic patients with HbA1c less than 8.0% (7.5 mg/dL) (P = 0.008 and P = 0.012, respectively). A similar pattern of distribution of lipoprotein (a) levels according to extent of control was seen in patients with insulin-dependent diabetes mellitus and noninsulin-dependent diabetes mellitus. No difference in the lipoprotein (a) distribution was noted between diabetic men and women. No correlation was observed between lipoprotein (a) levels and total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels. Conclusion: Lipoprotein (a) levels are elevated in poorly controlled diabetic patients. Increased levels of lipoprotein (a) may be a contributing factor to the high risk for atherosclerosis observed in diabetic patients.