Abstract : This study aimed to investigate the effect of COVID-19 on pulmonary function tests after 6-8 weeks of recovery, to confirm the necessity of the test to follow up the patients after recovery and to find out the possibility to use it as a workable procedure to indicate the severity of the previous infections. This a randomized-control study The study was conducted in Basrah City. Three groups of patients were divided based on the severity of the previous infection, Group 1 included the patients with previously severe infection; group 2 were the patients with previously mild infection and group 3 who never infected. Pulmonary function tests(PFTs) were measured in all groups using a spirometer. Data analysis showed that group 1 had a significant change in some PFT,6-8 weeks after recovery and this change was in form a restrictive pattern, while group 2 showed non- significant changes compared to group 3. COVID-19 might affect PFT after recovery in a way depended on the severity of the infection. This study pointed to the necessity of following up the previously infected patients and that measurement was workable test to indicate the severity of the previous infection.