\s=b\ The lipid content of the proximal jejunum, as studied by light microscopy with lipid histochemical staining methods, is determined in 14 fasting children with juvenile-onset diabetes mellitus. The results show that four children had greatly increased amounts of lipid, while six others had a mildly to moderately increased amounts of lipid present. The amount of lipid present appears to correlate most closely with the quality of control of the diabetes. These results indicate either that the clearance of exogenous lipid is impaired or that there is an increased endogenous synthesis of lipid within the intestine of the diabetic child, especially in those under poor control.(Am J Dis Child 131: [962][963][964][965][966][967][968][969] 1977) Hyperlipidemia is found in "wellcontrolled" diabetic children with an incidence of 9% to 24% and is frequently found in patients with uncontrolled diabetes mellitus.13 In recent years, the small intestine has been recognized as a possible impor¬ tant source of endogenous triglycéride and cholesterol synthesis.4 A 15-year-old child with juvenileonset diabetes mellitus was referred because of recurrent abdominal pain. A fasting peroral jejunal biopsy was From the