In human pathology, the association of generalized amyloidosis with chronic tuberculosis is a well known fact. Thus, in many cases, amyloidosis has been considered an immunopathy induced by tuberculosis. In our material, necropsies of aged persons, suffering from senile mental deterioration and affected by amyloidosis, often revealed signs of lingering pulmonary and lymphonodular tuberculosis. Systematic clinical investigations of senile patients endorsed these observations, demonstrating a rather frequent occurrence of acid-fast bacilli in smears and cultures of sputa and gastric washings. Also, a causal connection between tuberculosis and amyloidosis was shown in a series of experimentally infected guinea pigs. These studies indicate the possibility of an immunobiologic connection between amyloidosis in aged persons and lingering tuberculosis.