To study the clinical features of ankylosing spondylitis (AS) in Shantou, China, and assess the therapeutic effect of slow acting antirheumatic drugs (SAARD). Clinical and laboratory data as well as the results of SAARD treatment were analyzed in 370 consecutive cases (46 female) seen in the period 1983-97. All patients met the modified New York criteria for AS. HLA-B27 was present in 83 of 89 (93.3%) patients tested. Insidious onset was seen in 94.3% of the cases studied: 33.5% with disease onset prior to age 20 years, 53.5% between ages 20-30 years, and 98.1% of all under age 40. Low back pain/discomfort, peripheral arthritis, positive "4" test, and tenderness over the sacroiliac joints/lumbar spine were the most frequent symptoms and signs. With some exceptions, the extent of sacroiliitis and involvement of the hip and spine were closely related to disease duration. Average disease duration was shorter among patients diagnosed after 1989 than before. A total of 107 cases have been followed for more than 3 years, of which 57 patients persisted with SAARD treatment for more than 3 years. Forty-four of the 57 cases (11.9% of the total of 370 cases) resulted in a good prognosis. Early diagnosis of AS in Shantou, China, improved in the 1990s. SAARD were effective in the treatment of AS at least in a small portion of the patients. Patient compliance and longterm treatment were essential to obtain a better outcome.