Real Madrid and Atletico Madrid have both been hit with transfer bans spanning the next two windows.
The Madrid clubs can sign players in this current window, but will be unable to acquire new ones until 2017.
This was the same ban Barcelona were hit with and that just got lifted this month.
Real have been linked with a host of elite players, such as David de Gea and Eden Hazard, but will need to act now or wait 18 months in order to sign them.
A statement released by Fifa on Thursday confirmed the sanctions: “The Fifa Disciplinary Committee has sanctioned Spanish clubs Atletico de Madrid and Real Madrid for breaches relating to the international transfer and registration of players under the age of 18.
“The two clubs were found to have violated several provisions concerning the international transfer and first registration of minor players as well as other relevant provisions with regard to the registration and participation of certain players in competitions.
“Both clubs are to serve a transfer ban that prevents them from registering any players at national and international level for the next two complete and consecutive registration periods for breaching articles 5, 9, 19 and 19bis as well as annexes 2 and 3 of the Regulations on the Status and Transfer of Players (the “Regulations”).
“The transfer ban, which does not affect the current registration period at all, given that it opened before the decisions were notified, applies to each club as a whole – with the exception of the women’s, futsal and beach soccer teams – and does not prevent the release of players.
“Additionally, Atletico de Madrid and Real Madrid have been fined CHF 900,000 and CHF 360,000 respectively, while both clubs have been issued with a reprimand and given 90 days in which to regularise the situation of all minor players concerned.”