The Lipid Management Nutrition Outcomes Project was a multicenter prospective noncontrolled observational study in which a network of 51 registered dietitians (RDs) from practice settings across the United States implemented the 1998 Medical Nutrition Therapy Hyperlipidemia Protocol and collected outcomes. Difficulty recruiting RDs and enrolling patients revealed a gap between practice guidelines and clinical practice. Many RDs did not have laboratory values or follow-up visits required by the protocol. RDs able to follow protocol recommendations had the expected positive results. Within a 6-month period, 377 new patients presenting for lipid management met inclusion/exclusion criteria. Some follow-up data were available on 280 (74.3%) patients. There were follow-up lipid data prior to lipid-lowering medication changes for 219 patients. Reported mean dietary fat intake was reduced to <30% (P<0.0001). The population lost weight and increased exercise frequency (P<0.001, P<0.001). In the 175 patients with initial triglycerides <400 mg/dL (4.52 mmol/L), 44.6% had either a 15% drop in low-density lipoprotein cholesterol or reached low-density lipoprotein cholesterol goal. Lipid response occurred in 34.7+/-16.5 weeks with 3.0+/-1.4 RD visits. The Lipid Management Nutrition Outcomes Project highlights frustrations and values of outcomes monitoring in actual practice and identifies areas for practice advancement.