The measurement of C-reactive protein (CRP) using both standard and high-sensitivity CRP (hs-CRP) assays is becoming common in clinical practice. This article addresses the causes of CRP elevation and the use of different CRP assays in internal medicine, including cardiology, gastroenterology, rheumatology, infectious diseases, and oncology. We focus on the recent medical literature on the use of hs-CRP in cardiovascular disease risk stratification and management, including updated screening guidelines on the use of hs-CRP, such as those issued in 2009 by the Canadian Cardiovascular Society. We also discuss the Reynolds Risk Score, which incorporates hs-CRP and family history with more standard cardiovascular risk factors (eg, tobacco use, hypertension, and dyslipidemia) and frequently leads to improved recategorization of cardiovascular disease risk levels. As the recently completed Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) trial indicated that statin therapy decreases the vascular events among persons with elevated hs-CRP by half, even when cholesterol levels are low, the inclusion of information on hs-CRP values with other cardiovascular risk factors may assist physicians in medical decision making for patients.