Kidney damage in patients with arthritis is one of the most formidable viscerites. Nephropathy in rheumatological diseases is diverse and can be a component of the main disease (for example, lupus nephritis in patients with systemic lupus erythematosus), and its complication (AA-amyloidosis in patients with rheumatoid arthritis) or a consequence of the use of drugs for treatment of rheumatological conditions. Kidney damage in patients with arthritis can include the glomerular and tubular compartments of the kidney, or both. Despite the importance of early diagnosis of kidney damage in patients with arthritis, this issue is not well understood. A possible reason for this is a small number of kidney biopsies in patients with these diseases. The presence of proteinuria or an increase of serum creatinine level often automatically considered as AA-amyloidosis, while other possible morphological variants are not considered. This leads to the detection of nephropathy in the later stages, which increases the risk of developing of chronic kidney disease (CKD) and worsens the overall prognosis in patients with arthritis. The management of such patients depends on the pathology pattern of nephropathy. In this regards, early screening of nephropathy and determination of indications for kidney biopsy recommended in such clinical situations. Treatment of such patients should be carried out by a multidisciplinary team of internists, nephrologists, and rheumatologists. We present description of two cases of nephropathy in patients with rheumatoid arthritis and ankylosing spondylitis, illustrated by kidney pathology; histological nuances and clinical features are discussed. © 2020 JSC Vidal Rus. All rights reserved.