Three domestic short-haired cats with a history of anorexia and loss of body condition had high rectal temperatures, and a normocytic, normochromic anaemia. Two of them were also dyspnoeic, and thoracic radiographs revealed a diffuse, unstructured increase in radio-opacity involving all the lung lobes. Examination of Giemsa-stained blood smears and culture of blood monocytes revealed purplish-staining intracytoplasmic inclusions, in monocytes and lymphocytes, which occurred either singly or in aggregates. Electron micrographs of a buffy coat smear from one of the cats revealed round intracytoplasmic inclusions, with electron dense and lucid areas morphometrically similar to those found in other members of the genus Ehrlichia. An attempt to culture chlamydia from one of the cats was unsuccessful. The cats were treated successfully, one with tetracycline hydrochloride and the other two with imidocarb dipropionate.