A home appliance and a method of controlling the same are provided. The home appliance may include a controller that processes state data. The state data may include raw data representing an operation state of the home appliance. The controller may also output diagnosis result data representing whether or not an error has occurred in the home appliance. A tag device including a tag storage device may store the state data and the diagnosis result data, and a transmitting and receiving device may transmit the state data and the diagnosis result data when an external device is tagged.