We studied the impact of nurse case management (NCM) on blood pressure (BP), hemoglobin A1C, lipids, and diabetes complication screening. A 1-year randomized-controlled trial was conducted in two primary care clinics of the Penn State Hershey Medical Center. Diabetes patients were randomized to control group (CG) (n=182) who received usual care by their primary care provider and intervention group (IG) (n=150) who received additional NCM care, including self-management education, and implementation of diabetes guidelines. Primary outcomes included BP, A1C, lipid, process measures, and secondary outcome was diabetes-related emotional distress as assessed by Problem Areas in Diabetes (PAID). BP significantly decreased from 137/77 to 129/72 in IG as compared to an increase from 136/77 to 138/79 in CG after 1 year. PAID scores improved significantly in IG (from 23 to 10) due to reduced emotional stress. A1C (7.4) and LDL (105) were unaffected. Complications screening significantly improved in IG compared to CG: opthalmologic exam 26 to 68%, foot exam 47 to 64%, and nephropathy screening 34 to 72%. NCM improved BP, diabetes-related emotional distress, and process measures in primary care. Unchanged A1C and lipids might be due to a threshold effect. Intervention based upon initial risk assessment may prove more cost-effective.