Abstract : Measuring chest expansion is considered to perform in COVID-19 patient to assess the pulmonary function impairment as its usage to other interstitial lung diseases. The decrease of pulmonary function will affect the cardiorespiratory functional capacity. These problems demand an appropriate pulmonary rehabilitation programme aimed to returning the decent quality of life. Among 43 subjects we prescribed two types of breathing exercise: incentive spirometry and diaphragm breathing exercise. The chest expansion at three levels (axillary, nipple, and xiphisternum) was measured before and after breathing exercise; then average of its improvement was recorded. The assessment of functional capacity using 4-meter gait time test (4MGT) was also performed after sequence of breathing exercises. This study showed improvement of chest expansion on majority of subjects. Based on bivariate analysis using Spearman correlation, the p value was 0,012 (p <0,05) and coefficient correlation was 0,381. We can conclude that there was correlation between chest expansion improvement and functional capacity measured by 4MGT after breathing exercise in COVID-19 patient.