Six patientes are studied (five females and one male) in which disorders of consciousness varying from stupor to coma have occurred following variable periods of cerebral hipoxia caused either by cardiorespiratory standstill (five cases) or acute pulmonary injury. After a few hours they had generalized convulsives crisis of tonic-clonic type. As consciousness was regained they developped generalized myoclonic trembling of great intensity. Hence post-anoxic myoclonic encephalopathy is characterized. It is also called the Lance-Adams syndrome, in honor of the authors that described it in 1963. Five patients underwent electroencephalographic examination; the tracing showed typical myoclonus potentials in some, and characteristic diffuse brain injury in others. Electromyography was carried out in one patient, and cerebral computorized tomography in two others. The latter revealed an accentuated widening of sylvian cleft at the base in one them, specially on the right side, which explain his dementia-like picture. The biochemical analysis of the spinal fluid was normal in five cases.