How does Spain handle legal registration for those individuals without an existing double last name?

Last Updated on March 18, 2026 by Bruno Bianchi

Question

For those of you without an existing double last name, how does Spain handle you when registering for things like health care, etc. Do they just enter one last name?  Has anyone insisted you have a second last name?  Just wondering how everyone operates with one last name in a two last name world.

Answers

These are the answers of some Facebook group members:

“I’ve rarely run into this. When I WAS required to write a second last name on a form, I just wrote “–,” and that was that. No issues further down the road”

“I have generally used my middle and last name, since it matches what’s on my passport.”

“Make sure you put your first and second names as “nombre” here, if they are both on your passport. Don’t complete the second apellido.

Unfortunately, you will still have some problems as they will assume the second name is your first apellido. I found this very confusing to start with in doctors surgeries, where they’d call out “Mary” (my second name, which I never used before moving here) and expect me to stand up.”

“Until it’s time to become a citizen, use whatever is on your passport. If and when you become a citizen, you’ll need to take on two family names. The rules are a bit more complicated, but for the vast majority of people, they’ll be your father’s and your mother’s surnames.”

“I‘m American. I put my first name and middle name as nombre and my first and only surname as primer apellido. On some websites you are forced to enter something for segundo apellido. I have also just entered a blank space (no letters or punctuation) and the system usually accepts that.”

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Bruno Bianchi CEO & Spain Immigration Expert

Bruno Bianchi is the founder and CEO of Spainguru, Spain's largest expat immigration community with 150,000+ members. Since 2014 he has helped thousands of people relocate to Spain through expert guides, webinars and vetted professional services covering visas, residency, taxes and life in Spain.

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