Acute anterior uveitis (AAU) may be considered to be one manifestation of the seronegative spondylarthropathies of which ankylosing spondylitis (AS) is the prototype, especially when the patient is HLA-B27 positive. However, it is not yet clear under which circumstances a patient with AAU should be referred to the rheumatologist. In a retrospective study we evaluated the management of 68 consecutive HLA-B27+ AAU patients from a rheumatologic point of view. Although the majority (73%) showed rheumatic problems, only half (52%) of the patients was referred to a rheumatologist, due to problems in evaluation of clinical history and of x-ray reading of the sacroiliac (SI) joints. Because HLA-B27 typing will determine whether the AAU patients "at risk" have AS or a related arthropathy, we suggest using HLA-B27 typing in AAU patients as a diagnostic and prognostic aid. When the AAU patient is found to be HLA-B27 positive, the rheumatologist will be able to "split" these patients into those with AS and those without. Early diagnosis of AS in AAU patients is important as an early start of drug therapy and physiotherapy may prevent deformities and improve final rheumatologic outcome.