Over a five-year period 245 patients with uveitis were investigated at the Uveitis Clinic, Sydney Eye Hospital, for possible aetiological and relevant disease associations. Uveitis was anterior in 75% of patients, posterior in 21% and generalized in 4%. Anterior uveitis (AU) was idiopathic in 52% of cases. In patients tested for the HLA-B27 antigen, 47% were HLA-B27 positive, including all cases of ankylosing spondylitis (8% of cases) and Reiter's syndrome (3% of cases). There was a marked male predominance in patients with AU, especially in HLA-B27 positive individuals. Posterior uveitis (PU) was most frequently unilateral, chronic and idiopathic (24% of cases), whilst recognizable aetiologies included toxoplasmosis (20%), Behcet's syndrome (14%), sarcoidosis (12%) and pars planitis (12%). The peak age of onset in patients presenting with AU was 30 to 40 years, whilst patients with PU presented a decade earlier. There were no major differences between males and females in the age of onset of their uveitis.