Little is known about the lipid profiles and associated treatment patterns of patients in whom atherosclerosis is diagnosed. This investigation assessed and described the low-density lipoprotein (LDL) cholesterol levels and treatment patterns for hypercholesterolemia in patients with atherosclerosis who were treated in routine clinical practice. This retrospective database study used a random sample (1 million patients) from a national outpatient electronic medical record database (GE Medical Systems, Milwaukee, WI) and included patients with a diagnostic code for atherosclerosis (International Classification of Diseases [ICD]-9 code of 440.xx or 414.x or 437.x) between January 2004 and March 2006. Use of hypercholesterolemia medications at the time ICD codes for atherosclerosis were recorded and thereafter was documented. Patient demographics, comorbid conditions, baseline LDL cholesterol (closest value within 6 months of the diagnosis date), and follow-up LDL cholesterol (after diagnosis) were also documented. A total of 10,637 eligible patients had an ICD diagnostic code for atherosclerosis. Most patients (61.3%) were not taking any dyslipidemia medication at the time of and after atherosclerosis diagnosis. A total of 3% were prescribed therapy with a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor (statin) before the time of atherosclerosis diagnosis, and 25% were prescribed a statin after diagnosis. Approximately 62% of patients with atherosclerosis did not have a baseline LDL cholesterol estimate. Of patients with LDL cholesterol recorded at diagnosis (n = 4,067), 24% had LDL cholesterol > or = 130 mg/dL (1 mg/dL = 0.02586 mmol/L), 53% had LDL cholesterol > or = 100 mg/dL, and 87% had LDL cholesterol > or = 70 mg/dL. Among patients with LDL cholesterol > or = 100 mg/dL at diagnosis, 57% were not prescribed statin treatment after diagnosis. Of those with baseline and postdiagnosis LDL cholesterol values (n = 1,395), 49% had baseline LDL cholesterol > or = 100 mg/dL. Among patients on statin or any other hypercholesterolemia therapy after diagnosis who had baseline and follow-up LDL cholesterol values (n = 682), 87% had baseline LDL cholesterol > or = 70 mg/dL and 51% had baseline LDL cholesterol > or = 100 mg/dL, whereas 82% had postdiagnosis LDL cholesterol > or = 70 mg/dL and 43% had postdiagnosis LDL cholesterol > or = 100 mg/dL. The results from this study, which was conducted in a routine clinical practice setting, indicate the opportunities and the need for better monitoring and management of lipid levels in patients with atherosclerosis.