A 16-year-old boy with primary intestinal lymphangiectasia presented with peripheral edema of 6 weeks duration. Laboratory and radiological studies included absolute lymphopenia, hypoalbuminemia, steatorrhea, abnormal stool 51Cr-albumin value, edema of small intestinal folds, dilated mesenteric lymphatics, as well as bilateral filling defects in external and common iliac lymph nodes. Abdominal CT scan revealed a possible periaortic mass. Small intestinal biopsies demonstrated normal villous architecture with dilated lacteals, and electron microscopy revealed enterocytes with normal as well as blunted microville, enlarged, dilated lacteals and intercellular vacuoles. An exploratory laparatomy was performed and revealed no masses but dilated serosal lymphatic vessels. Medical treatment, including marked restriction of long chain triglyceride intake, resulted in loss of peripheral edema, weight stabilization, and normal activity.