A study was undertaken to ascertain the appropriateness of lipid screening and management per the Third Report of the Adult Treatment Panel National Cholesterol Education Program (ATP III) guideline in a sample of North Carolina primary care practices. Demographics, cholesterol values, and comorbid conditions were abstracted from the medical records from 60 community practices participating in a randomized practice-based trial (Guideline Adherence for Heart Health). Eligible patients were aged 21 to 84 years, seen during the baseline period of June 1, 2001, through May 31, 2003, and who were not taking lipid-lowering therapy. Multivariable logistic regression was utilized to assess whether age, sex, race/ethnicity, diabetes, cardiovascular disease, ATP III risk category, or pretreatment low-density lipoprotein (LDL) influenced treatment. Among 5031 eligible patients, 1711 (34.5%) received screening lipid profiles. Screening rates were higher with older age, diabetes, and cardiovascular disease. No large differences were seen by sex. Among patients screened (mean age, 51.6 years; 57.9% female), 76.6% were appropriately managed within 4 months. In adjusted analyses, older age was associated with less appropriate treatment (odds ratio [OR] per 5 years, 0.91; P=.01), and patients with LDL cholesterol ≤130 mg/dL (OR, 18.8; P<.001) and the low-risk group (OR, 27.5; P<.001) were more likely to be managed appropriately compared with patients with LDL ≥190 mg/dL and those at high risk. Among 375 patients eligible for drug treatment, those with LDL levels between 131 and 159 mg/dL were much less likely to be treated (OR, 0.15; P<.001) compared with those with LDL >190 mg/dL, whereas risk category did not influence treatment. The challenge facing implementation of ATP III guidelines is much greater for intermediate- and high-risk patients than for low-risk patients.