Erdheim-Chester disease is an idiopathic condition characterized by infiltration of the heart, lungs, retroperitoneum, bones, and other tissues by a fibrosing xanthogranulomatous process composed of xanthomatous histiocytes and Touton giant cells. This condition is often fatal, with death due to cardiomyopathy, severe lung disease, or chronic renal failure. Ocular findings with this potentially fatal disease are rare. We report the clinical and histopathologic findings in two cases of bilateral xanthelasmas and bilateral orbital infiltrates in association with Erdheim-Chester disease. The first patient was a 38-year-old man with cardiovascular and renal disease and severe retroperitoneal fibrosis. The massive orbital infiltration produced bilateral blindness. The second patient was a 77-year-old man with severe cardiovascular disease and retroperitoneal fibrosis. The diagnosis was confirmed in both patients with retroperitoneal and orbital biopsies. Both patients had the unusual occurrence of bilateral xanthelasmas with bilateral, diffuse orbital masses, eye findings that should alert the clinician to the possibility of this serious systemic disease.