An electron microscopic observation in a tonsil of a patient with early juvenile neuronal ceroid-lipofuscinosis (NCL) demonstrated characteristic lipopigments in lymphocytes, i.e., fingerprint profiles (FPP) and granular matrixes. While numerous FPP, curvilinear profiles (CLP) and granular matrixes were found in reticulo-endothelial and plasma cells, tonsillar lymphocytes contained only FPP and granular matrixes as seen in circulating lymphocytes. These findings suggest that a tonsil biopsy, an easy and simple technique, may provide more reliable information than a skin biopsy not only for the diagnosis of but also for differentiating the clinical forms of childhood NCL.