The efficacy of intensive inpatient physiotherapy was retrospectively analysed in 505 adult patients with ankylosing spondylitis (AS). Eight different measures of thoracic and spinal mobility were collected from the patients' medical records. Recovery in terms of the following measures was 7 to 37% when results after rehabilitation were compared to those taken before: thoracolumbar flexibility (TLF) 15%, the Schober test 12.4%, occiput to wall distance (OWD) 30.8%, cervical rotation 22.6%, chin to chest distance (CCD) 21.7%, finger to floor distance (FFD) 36.6%, chest expansion (CE) 31.3%, vital capacity (VC) 7.4%. Changes in all measures were statistically significant (p less than 0.001). OWD, CE and FFD showed greatest improvement. The average increase in CE was about 1 cm in both sexes and the average increase in VC200 ml in men and 270 ml in women, which indicates improvement in ventilatory capacity. Mobility in the majority of patients improved, though in 2 to 8% range of motion (ROM) deteriorated during the course.