A method of transmitting blocks of data, in which, for at least one of the blocks of data, at least one parameter associated with this block of data is transmitted, the parameter representing the relative importance of the block of data associated with this parameter within the message transmitted by all the blocks of data. The data is coded by a channel coding method which does not take into account the parameter. Correlatively, the invention also concerns a decoding method associated with this transmission method. This way, data judged to be more important than other data may benefit from a channel decoding of higher quality. The methods described herein have application to devices and appliances implementing these methods.