A 54-year old man had severe inflammatory polyarthritis 10 days after the onset of an acute febrile illness that was serologically documented to be psittacosis. The pattern and chronicity of the articular symptoms, the response to nonsteroidal anti-inflammatory agents, and the presence of HLA-B7-CREG strongly suggest that this was a reactive arthritis. The association of psittacosis and reactive arthritis has previously been reported in the British literature, but this may be the first reported North American case.