This paper is part of a study on the electron microscopy of protein-energy malnutrition, using a rapid autopsy protocol. Samples of voluntary muscle, obtained from eight children dying of severe oedematous malnutrition, were fixed in glutaraldehyde within 75 minutes of death. Atrophy of myofibres, increased prominence of satellite cells, and segmental necrobiosis were seen by light microscopy. Electron microscopy showed variable depletion of myofibrils. In the most severe case, there was focal absence of myofibrils, also disorganized Z lines, and absent M bands. Residual atrophic myofibrils measured less than 0.1 micron in width. Other specimens showed sarcomere disorganization, mitochondrial swelling, glycogen depletion, sarcoplasmic oedema, and focal contractions of sarcomeres. Though non-specific, rigor may be accelerated by free radical damage, calcium release into the cytosol, and low supplies of high-energy phosphates. These conditions may exist in severe malnutrition, complicated by terminal infection and metabolic disturbances.