This report is the first in an annual series and covers the first full year of the new complaint handling system for the NHS. The Ombudsman warns that the NHS is missing a rich source of free and readily available information about patients by failing to listen and learn from complaints. The report's scope includes previously unpublished data about the number and type of complaints received by the Ombudsman in 2009-10 for every trust and strategic health authority region in England. It shows how many complaints were received and the outcomes of the complaints investigated. It reveals that 15,579 health complaints were closed by the Ombudsman in 2009-10 and that the two most common reasons for complainants to be dissatisfied with the NHS were failings in clinical care and treatment and the attitude of staff - a poor explanation or an incomplete response were the most common reasons given for dissatisfaction with NHS complaint handling. It presents a perspective not seen before: a national picture of what happens when mistakes occur and the NHS fails to put things right and highlights how often the Ombudsman needs to get involved just to ensure the NHS apologises when a mistake has been made. As the report shows, poor complaint handling can make a difficult situation worse for patients and their families. Poorly handled complaints can also escalate, creating unnecessary demands on NHS resources whilst resolving complaints effectively need not be costly. The report also features patients' stories taken from the Ombudsman's case files