Spondyloarthritis (SpA) usually follows a chronic disease course that requires regular medical care and monitoring to control for increased disease activity and to maintain physical function. This Review describes the instruments and imaging techniques available for monitoring SpA in clinical practice. Specifically, questionnaires, physical examination and laboratory tests that can be used to measure physical function, disease activity and pain are discussed. Furthermore, the value of different imaging techniques, including conventional radiography, MRI and ultrasonography, for use in the clinic is described. In the past decade, most of the work on standardizing the monitoring of outcome measures in SpA has focused on ankylosing spondylitis, and similar developments are currently in progress for the monitoring of psoriatic arthritis. This Review, therefore, will focus on these disorders.