This article presents three patients with acute calcific periarthritis (ACP) of the hand and wrist. ACP is an unusual, painful, monoarticular, periarticular inflammatory process associated with juxtaarticular deposits of amorphous calcium hydroxyapatite. ACP is a distinct clinical subset of hydroxyapatite deposition disease. ACP has a high rate of misdiagnosis because of its rare occurrence and its clinical resemblance to other entities. Clinical presentation may simulate infection, and the associated periarticular calcifications may be mistaken for gout, pseudogout, or other entities. One third of patients with ACP provide a history of antecedent trauma. Treatment is conservative. Patients typically will have a reduction in symptoms within 4-7 days after the acute onset of pain. Radiographically, the periarticular mineralization usually resolves or markedly decreases within 2-3 weeks, although on occasion, some calcifications may remain visible for months. Failure to recognize and correlate the typical clinical and radiographic presentation of this disease may lead to unnecessary diagnostic tests, invasive procedures, and inappropriate medication.