It is well known now that COVID-19 can negatively influence different human body systems. Only few reports concerning avascular necrosis after COVID-19 have been accessible until now. The large-scale use of life-saving corticosteroids in COVID-19 treatment role is discussed in these papers. Four patients with bilateral avascular necrosis of the femoral head after being treated for COVID-19 infection are demonstrated. The doses of prednisolone used in three cases were 4000 mg, 746 mg and 533 mg. Сorticosteroids were not used for the treatment of one patient. Our data shows that the timing of the development of avascular necrosis after COVID-19 is significantly shorter than the terms of the osteonecrosis development in patients without COVID infection. Two patients out of four (sisters, 32 and 30 years old, 533 mg prednisolone dose and no corticosteroids) have burdened familial history (myocardial infarction, hypertension, thrombosis). Probably in these two sisters, hereditary vascular factors played some role in the genesis of avascular necrosis of femoral head. Further accumulation of evidence is needed to understand the characteristics of osteonecrosis after COVID-19. It is possible that several factors synergistically affect the development of this disease.