Ankylosing spondylitis (AS) is a chronic inflammatory disease requiring regular medical care and monitoring to alleviate symptoms, maintain function, identify disease progression and initiate appropriate, timely therapies. Monitoring of the AS patient in clinical daily practice should not only include general history taking and physical examination, but also incorporate specific concepts, pertaining to the disease, which will aid in the detection of disease progression, the requirement of therapeutic intervention and the response to therapy. The Assessments in AS (ASAS) international working group has defined a core set of disease concepts that should be a part of everyday clinical record-keeping in AS, and has identified and validated measurement instruments corresponding to these health concepts, which can easily be incorporated into clinical practice. The group has also developed recommendations for management and a consensus statement for the use of biological therapies in AS, which includes recommendations for the monitoring of AS patients receiving these therapies. This chapter reviews the recommendations for monitoring AS patients in daily clinical practice, with particular regard to those receiving biological treatments.