Lay persons ("care guides") without previous clinical experience were hired by a primary care clinic, trained for 2 weeks, and assigned to help 332 patients and their providers manage their diabetes, hypertension, and congestive heart failure. One year later, failure by these patients to meet nationally recommended guidelines was reduced by 28%, P < .001. Improvement was seen in tobacco usage, blood pressure control, pneumonia vaccination, low-density lipoprotein cholesterol levels, annual eye examinations, aspirin use, and microalbuminuria testing. Care guides served an average of 111 patients at an annual per patient cost of $392. Further testing of this model is warranted.