The acreditation for the current Master in Mathematical Research expires the present academic year. Starting the year 2012/2013, and upto a final approvation from the Ministery, there will start a new Master in Advanced Mathematics (see its structure).
There will be three different deadlines for admission for the year 2012/2013: 10-28 February, May 16 till June 15 and 6-13 September (check here the the general regulation for the Masters at University Complutense of Madrid, as well as the procedure for admission and registration). In case of any doubt, you are welcome to send an e-mail to the Master coordinator, Enrique Arrondo.