Many patients seen in primary care have chronic kidney disease (CKD), an increasingly prevalent, costly, and underappreciated public health problem. According to the third National Health and Nutrition Examination Survey (NHANES III), 800,000 Americans have serum creatinine levels of 2.0 mg/dL or greater, and 6.2 million people have levels of 1.5 mg/dL or greater . Although these creatinine values include those only modestly greater than the upper limit of normal and therefore suggest very mild and clinically insignificant disease, they correspond to glomerular filtration rates of less than 60 mL/min/1.73 m2. This translates into approximately a 40% reduction in renal function. CKD is a multifaceted disease process. Objectives of nephrology interventions for CKD include (1) a reduction in the incidence rates for end-stage renal disease (ESRD), (2) an increase in screening for kidney disease in persons with hypertension and diabetes mellitus, (3) an increase in the treatment to preserve kidney function in persons with diabetes and proteinuria, (4) optimization of blood pressure control in persons with kidney disease, and (5) an improvement in pre-ESRD care to decrease ESRD-related morbidity, mortality, and costs . Early intervention will likely have the greatest impact on slowing progression of CKD and thus delay the development of ESRD. However, before a physician can initiate effective treatment or refer a patient to a nephrologist, a diagnosis must be made. It can be difficult to diagnose CKD in its early stages, when it is usually asymptomatic. Challenges include identifying patients at risk and applying appropriate screening, interpreting flawed measures for evaluating renal function, and contending with the lack of uniform nomenclature in the medical literature. This article will discuss these challenges and recommend strategies for overcoming them.