The collagen, elastin, total sugar, and nonscleroprotein content was evaluated in 32 samples of saphenous varicose vein and in 34 controls. A significantly lower collagen and elastin content was found in the varicose samples without correlation with the degree of pathologic broadening. Otherwise the total sugars and the soluble nonscleroproteins were found to be increased in varicose samples. The results are more significant when expressed as milligrams per surface unit of endothelium. Our data support the hypothesis that the decrease in collagen and elastin content is a primary rather than secondary change.