Polyarthritis is a well-recognized manifestation of sarcoidosis, but the various series of cases reported in the literature reveal considerable variation in its incidence as well as in its clinical manifestations. Three major types of sarcoid polyarthritis are defined, as distinguished by their clinical and pathological features. Two of these types are usually seen in conjunction with the subacute or transient form of sarcoidosis and, in most cases, are accompanied by erythema nodosum. They differ markedly in severity, but their prognosis is uniformly good. The third type, in contrast, is of a chronic nature and is often associated with permanent joint changes. Mild joint manifestations are a frequent finding in sarcoidosis, but more severe arthritis is relatively rare.Two cases of sarcoidosis, presenting with severe polyarthritis, are reported in detail, and cases seen in Halifax hospitals during the period 1954 to 1964 are reviewed.