As from roughly March last year (2007) it is now a legal requirement for you in Spain to have a residency certificate. Before that date it was not necessary, but the EU pushed Spain into a corner and this is the way they reacted.

So ..... as soon as you are resident in this country you need to apply, usually to your local Police station, for said certificate within 30 days

You need to complete Form EX 16 and then queue normally for a very long time. After the form is accepted they will give you a payment slip which you take to the nearest bank. Take the slip back to the Police station and they will issue you with the certificate. The cost is about €6.80, and you dont need photographs. Take your passport and you padron certificate.

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