Background: Since the COVID-19 outbreak the researches have been focused only on the infection spread prevention and treatment. Right now, there is no biomarker available that can expect people who are at high risk of susceptibility and symptoms severity of COVID-19 infection.  Recent studies indicate that a persons' vulnerability and severity of COVID-19 infection may be significantly influenced by their ABO blood group. Aim: To explore the association between ABO blood grouping and both risk and severity of symptoms among post COVID-19 infection patients. Methods: A retrospective observational research design was used. A convenient 500 post COVID-19 infection individuals from Beni-Suef University hospital were participated in the study. Tool I patient characteristics and tool II COVID-19 related data were used for data collection. Results: The findings illustrated that 16.2% exposed to severe COVID-19 symptoms, blood group A represents the highest frequency 34.8% among other blood groups while blood group O depicts the lowest frequency 17.2%. Moreover, severity risk for blood group B individuals was significantly higher than blood group A individuals (OR= 1.795, 95% C.I = 1.027– 3.137). In addition, a statistically significant correlation was found between increased age and severity of symptoms “moderate and severe" (c² = 41.626, p < 0.001). Conclusion and recommendations: As blood group A showed the highest frequency, following safety precautions is critical for those people, and in the event of a COVID-19 infection, strict treatment, thorough observation, and monitoring are required. Further researches about adding further doses of vaccination for blood group A individuals.