In Ankylosing Spondylitis (AS), thoracic range of motion is often greatly limited. The objective of the study was to describe the effects of 12 weeks of Glossopharyngeal Insufflation (GI) training in patients with AS. Dynamic spirometry included vital capacity, forced expiratory volume, and peak expiratory flow. Thoracic and lumbar range of motion was assessed by tragus-to-wall distance, modified Schober test, and tape measure. Disease activity, activity limitation, and health perception were assessed using the BAS-Indices, and tension in the thoracic region during GI was assessed using the Borg CR-10 scale. Adherence to training was recorded in an activity log, along with any remarks on the training. Ten patients were recruited and six male patients fulfilled the study protocol. Three patients were able to learn GI by exceeding their maximal vital capacity with 5% using GI. A significant increase in thoracic range of motion both on costae IV (P = 0.04) and at the level of the xiphoid process (P = 0.04) was seen. Thus, patients with AS can practice GI, it is safe if maximal exertion is avoided, and patients with some mobility in the chest can increase their lung function substantially by performing GI during 12 weeks.