Eighty-five patients with acute Yersinia arthritis were seen in followup for a mean of 10 years. During that time, peripheral joint symptoms occurred frequently (51.8%), but these symptoms were mild (45.9%). Development of a new reactive arthritis (4.7%) or chronic arthritis (2.4%) was uncommon. One-third of the patients experienced low back pain, and one-third of the patients had radiologic evidence of sacroiliitis. The presence of sacroiliitis was more frequent in patients with low back pain (46.7%) than in those who did not have symptoms (21.2%). More patients with HLA-B27 had low back pain and sacroiliitis, but there was no association of this genetic factor with the residual symptoms in peripheral joints.