Significant amounts of glycosaminoglycans (GAGs) were found in amyloid fibril preparations. Using two-dimensional electrophoresis to fractionate GAG mixtures, we quantified and identified for the first time the GAGs of the fibrils from carpal synovium of patients with amyloid associated with chronic hemodialysis. The total GAG content was small, but the GAG distribution (high relative content of chondroitin sulfate and hyaluronic acid and lack of the other GAGs) was unique, unlike that for the other amyloid fibril preparations. The amyloid-rich heart, liver, and spleen tissues, as well as the fibrils isolated from these tissues of patients with systemic forms (primary amyloid and secondary amyloid) of amyloid disease, were also analyzed for GAGs. Fibrils from heart tissue of a patient with primary amyloidosis, now examined for the first time, contained four major GAGs (chondroitin sulfate, dermatan sulfate, hyaluronic acid, and heparan sulfate).