Background: During the COVID-19 pandemic, patients with myasthenia gravis (MG) are most likely to be affected by this situation. Corticosteroids and immunosuppressant agents increase the risk of severe infection. Furthermore, viral infection and some medications in COVID-19 may exacerbate MG symptoms. Case description: We presented three patients with MG who contracted COVID-19. All of the patients had a favourable outcome. Only one patient who was not treated with corticosteroids or immunosuppressant therapy experienced deterioration of MG symptoms, while the other patients who received immunosuppressant therapy did not develop MG exacerbation. Surprisingly, azithromycin did not provoke myasthenic crisis (MC) in patients with normal MGFA classification. Conclusion: Using immunosuppressant agents may not lead to MG deterioration and may not be related to unfavourable outcomes. © 2021 The Author(s)