Since ankylosing spondylitis usually starts at an early age, the socioeconomic impact of the disease on the patient and on society can be important. Several studies have reported substantial work disability, but there is considerable variation among countries. While withdrawal from work is associated with an older age at diagnosis and manual jobs or a lower educational level, sick leave in those with a paying job is associated with disease activity and physical functioning. The yearly mean total (direct and productivity) costs of AS are US$6,720 per patient in the USA and Euro 9,462 per patient in Europe when the human capital approach is used to calculate the productivity costs. A cost-effectiveness study on spa-therapy in AS shows that the clinical benefits of (expensive) treatments can be reached within acceptable costs.