If acute arthritis occurs in the elderly in addition to typical degenerative, load-related joint complaints, this is often induced by crystal deposition. The crystals lead to activation of the immune system resulting in acute inflammation. In addition to gout, calcium pyrophosphate deposition (CPPD) disease in particular must also be taken into consideration. Diagnostically important are imaging techniques, e.g. early specific alterations of cartilage can be shown by joint sonography and later calcium pyrophosphate crystals can be detected as cartilage calcification (chondrocalcinosis) by radiography. Important for the diagnosis of crystal arthropathy is usually the microscopic detection of specific crystals in the synovial fluid and is supported by exclusion of septic arthritis by arthrocentesis. In contrast to gout, which can be well controlled by the pharmaceutical lowering of uric acid levels, there is no causal therapy for CPPD disease so far. As CPPD may occur as a secondary effect in metabolic disorders, such as hyperparathyroidism or hemochromatosis, it seems to be important to search for the underlying disease. The following article presents the current knowledge on clinically relevant aspects of the pathogenesis, diagnosis and therapy of CPPD disease.