The article contains current data on the pathogenesis, classification and diagnosis of amyloidosis. Amyloidosis is a group of diseases associated with extracellular deposition of protein with abnormal conformational structure. Beta structure provides resistance to proteolytic enzymes. We know many different proteins which have amyloidogenic properties. The most frequently observed type of amyloidosis is AL amyloidosis, the second being amyloidosis AA. Renal amyloidosis is common and depends on the type of amyloidogenic protein. Diagnosis is difficult and multidirectional. Amyloidosis is a chronic disease associated with poor prognosis, requiring a precise diagnosis concerning its type, thus allowing to determine the prognosis.