Objective To discuss the clinical and MR imaging characteristics of patients with delayed encephalopathy after acute carbon monoxide (CO) poisoning (DEACMP). Methods The clinical and imaging data of 23 patients with DEACMP,admitted to our hospital from January 2007 to July 2011,were retrospectively analyzed. Results The dominant symptoms of DEACMP included mentally falling in 21 patients (91.3％),extrapyramidal impairments in 15 patients (65.2％),and mental and behavioral abnormalities in 12 patients (52.2％).Cranial MRI features included bilateral subcortical white matter and/or periventricular white matter damage in 11 patients, bilateral basal ganglia (mainly bilateral globus pallidus) damage in 4,and damage in both sub-cortical white matter and basal ganglia in 8.The prognosis of patients with simple globus pallidus damage was better.All patients were given high pressure oxygen,medications improving the cerebral blood circulation,brain nutritional medicine and symptomatic treatment with total efficiency reaching 86.9％. Conclusion Cranial MRI features has important values in early diagnosis,treatment efficacy evaluation and prognosis estimation of patients with acute DEACMP; full-time course of hyperbaric oxygen therapy is very important and effective.