Objective: The clinical features of COVID-19 range from asymptomatic disease to severe pneumonia or even death. Therefore, many researchers have investigated the factors that could affect the severity of COVID-19. We aimed to assess the impact of aero-allergen sensitization and allergic diseases on the severity of COVID-19. Materials and Methods: We included 60 adult patients with symptomatic COVID-19 and allocated them into two groups equal in number as having severe and non-severe COVID-19. We evaluated the demographic features and allergic diseases in addition to clinical, laboratory and radiological findings of COVID-19. Skin prick tests (SPTs) with common aero-allergens, serum total IgE levels and blood eosinophil counts were evaluated 3 months after the patient’s recovery from COVID-19. Results: The mean age of the patients was 52 ± 11 years and 73.3% of the patients were male. There was no significant difference between the two groups in terms of age, gender, smoking habits, obesity and comorbidities. Although the frequency of sensitization to aero- allergens and the allergic diseases were similar, the history of allergic diseases in the family was higher in the severe group (p<0.001). The polysensitization in SPTs was associated with the presence of a cytokine storm during the infection (p=0.02). Total IgE levels and blood eosinophil counts were not significantly different between the two groups. Conclusion: The presence of atopy or allergic diseases does not seem to be related to the severity of COVID-19. However, polysensitization and a family history of allergic diseases are more prominent in those having a cytokine storm and severe COVID-19, respectively.