The clinical characteristics of and treatment approaches for critical illness polyneuromyopathy (CIPNM) are reviewed.CIPNM is an acute axonal sensory-motor polyneuropathy that tends to occur after the development of respiratory insufficiency in patients with systemic inflammatory response syndrome, sepsis, or multiple-organ dysfunction syndrome. Numerous mechanisms have been proposed to explain the pathophysiology of CIPNM, most of which are complex and not fully understood or proven. While the rate of intensive care unit-acquired weakness varies greatly among patients, an estimated 25-85% of critically ill adult patients will develop neuromuscular weakness, most commonly CIPNM, during hospitalization. While no specific pharmacologic treatments exist for CIPNM, the outcome for most patients is related to the severity of the illness and neuromyopathy, as well as early intervention to treat the underlying condition. Electrophysiologic studies, such as electromyography, electroneurography, and muscle and nerve biopsies, are considered the gold standard for aiding in the diagnosis of CIPNM. Preventive measures such as the early provision of appropriate nutrition, glucose control, physical rehabilitation, and the cautious use of medications such as corticosteroids and neuromuscular blocking agents (NMBAs) can help reduce the occurrence of CIPNM.CIPNM is an acute axonal sensory-motor polyneuropathy commonly seen in critically ill patients with sepsis and multiorgan failure. While no specific pharmacologic treatments exist, preventive measures such as the early provision of appropriate nutrition, glucose control, physical rehabilitation, and the cautious use of medications, including corticosteroids and NMBAs, can help reduce the incidence of CIPNM.