In the last decades a lot of studies have done to check the Pilates' exercises' positive effects on the body and usage of this method in rehabilitation and physiotherapy field. As there are too many complication people face to because of bad posture we decided to purpose our current study on determining the effects of Pilates' exercises on posture and chest mobility. The group of ten medical students served as subjects in this study. All of them were healthy and young in the range of 20-26 years old. All they performed the basic mat Pilates’ exercises once a week in a 10-week period, each session was 50-minute consisting of basic core and back muscle strengthening program mixed with special Pilates breathing exercises. All the subjects underwent special tests performed by one of the last year physiotherapy students. The outcomes of the tests were recorded before and after the 10-week period of study. The tests included in this study were: Schober’s test, finger to the floor distance test, occiput to wall distance test, distance between to scapulas test, and distance between acromion to opposite anterior superior iliac spine test. We demonstrated improvement in the occiput to wall distance (p<0.002), in the distance of acromion to opposite anterior iliac spine (p<0.001 in the right side and p<0.002 in the left side), in the scores of Schober's test (p<0.001), and in the finger to floor distance. There was a linear correlation between the occiput to wall distance and the distance of acromion to opposite anterior iliac spine (correlation coefficient=-0.55057). The distance between the inferior angles of scapulas did not change significantly. In contrast, there was a significant increase in the chest expansion (p<0.005). According to our findings we conclude that Pilates' exercises can be effective in improvement of the body posture and chest expansion. It is supposed that this method is suitable for physiotherapy to cure and treat some diseases like chronic lower back pain, chronic obstructive disease, ankylosing spondylitis and so many diseases which are related to the spine mobility, stability, and flexibility. Pilates’ exercises are easy to master and can be used within a personal activity routine. It can be an adequate training for young healthy people also to improve the posture and chest mobility.