Although many metabolic and endocrine diseases have been reported to predispose to calcium pyrophosphate dihydrate crystal deposition, the validity of many of these associations remains unclear. A critical review of the literature relating to these associations, with illustrative cases and data derived from the authors' own experience, is presented. It is concluded that there is good evidence to associate hypophosphatasia, hypomagnesemia, and hyperparathyroidism with chondrocalcinosis and acute attacks of "pseudogout." Meta-analysis also suggests a small but significant association between hypothyroidism and chondrocalcinosis. Hemochromatosis stands alone in clearly associating not only with chondrocalcinosis but also with structural change and chronic arthropathy. The biochemical mechanisms that may produce these various associations are discussed. Recommendations are made concerning appropriate screening for metabolic and endocrine disease in patients with chondrocalcinosis.