Critically ill partients may develop muscle weakness or paralysis during the course of sepsis and multi-organ failure. Neuropathy, myopathy, or both have been suggested as causes. We observed a case of peripheral neuropathy and mypoathy during the course of sepsis and multi-organ failure in a 42 year old woman. The electrophysioligical studies, peripheral nerve and muscle biopsy confirmed the involvement of both peripaheral nerve and muscles.