Background: There is a wide variety of CT radiological findings of COVID-19 infection, this study aimed to analyze retrospectively the similarities and differences of CT radiological findings between first and second waves in the confirmed coronavirus patients.  Materials and methods: comparative retrospective study between two COVID-19 pandemic waves was conducted on 1000 patients who were diagnosed as COVID-19 patients, at Assiut University hospital, 500 patients in the period from May 2020 to August 2020, while the other 500 patients were in the period from October 2020 to January 2021, all underwent MSCT chest and a comparison between similarities and differences of CT radiological findings was done. Results: Both waves showed nearly the same mean and percentage of total CT severity score with no significant difference between them as p-value > 0.05. There is also a positive moderate correlation between age and total MSCT severity score of the lung in the first wave (r=0.51, p-value<0.001), while a significant positive mild correlation in the second wave (r=0.31 and p-value <0.001), atypical findings were encountered in the second wave more than in the first wave with the most common one was pulmonary fibrosis by (7.2%). Conclusion: Great similarity in CT radiological findings between the two COVID-19 pandemic waves was detected. However, the main difference between them was in the severity of lung involvement in different age groups and demonstration of atypical findings which was more common in the second wave.