Objective: COVID-19 has been introduced by the World Health Organization as a health emergency worldwide. Although more than 5% of the patients with COVID-19 require hospitalization, there are still no clear guidelines on patients' discharge time and factors influencing post-discharge outcomes. This study aimed to determine risk factors for readmission in the patients with COVID-19 admitted to hospital. In this prospective study, 416 discharged patients with a minimum follow-up of one month and the need for readmission were recorded. Evaluated characteristics included age, gender, CT scan, RT-PCR test and treatment modalities. After describing the data, any relationship between the patients' characteristics and readmission was assessed and predictive factors of readmission risk were estimated using regression model. The data were analyzed through STATA and P value less than of 0.05 was considered significant.Results: Regarding readmission, 51 patients were readmitted during the study period. The median follow-up time was 20 days (IQR: 7-120) and the mean follow-up time was 61±11.2 days. The mean duration of first hospitalization was 5.5 days and the rate of readmission of the patients between 30 and 60 days after discharge was 7.6% and 8.1%, respectively. The median age of these patients was 67 years (IQR: 53-78). About 65% of readmitted patients had underlying disease. The difference in readmission time was based on blood creatinine level and lung involvement. The odds ratio of readmission in the patients with abnormal creatinine levels (higher and equal to 1.2 mg/dl) and diabetes was equal to 2.15 and 3.43, respectively. Also, the odds ratio of readmission in the patients with basal lung involvement was 4.16. The highest readmission rate was 30 days after discharge. Age over 60 years, underlying disease especially diabetes, high creatinine level and lung involvement were the most important predictors of readmission in the patients with COVID-19.