Fewer than half of elderly people who had suffered hip fractures got rapid treatment for their pain and some departments failed to provide adequate care to patients who had taken paracetamol overdoses.
The Healthcare Commission, the Government's NHS watchdog which made the survey, said waiting times in A&E departments had improved but there were "serious variations" in the quality of care.
Critics have said the Government's target for all patients to be treated in A&E within four hours had skewed clinical judgement and led to a decline in quality of care. A spokesman for the commission said there was no evidence for this.
There are 202 major A&E departments in England open 24 hours a day dealing with between 20,000 and 130,000 patients a year. In the best departments, all patients received pain relief within an hour but in the worst, fewer than 20 per cent did.
Anna Walker, the chief executive of the commission, said: "A&E departments have made great strides in improving services, in particular on waiting times which are very important to patients. They now have to go the extra mile ... and that means focusing on quality as well."