Hypoxemic respiratory failure caused by coronavirus disease 2019 (COVID-19) may lead to prolonged intensive care unit stay and mechanical ventilation. Critically ill patients often develop intensive care unit acquired weakness (ICUAW), which is an umbrella term that encompasses critical illness polyneuropathy and critical illness myopathy. The aim of this paper is to report the clinical, neurophysiological, and radiological findings suggesting critical illness myopathy in three patients with critical COVID-19. Muscle magnetic resonance imaging may serve as a diagnostic tool for critical illness myopathy. Weaning failure and generalized muscle weakness with preserved sensation and cranial nerve function should alert physicians for ICUAW.