"Notarios Publicos" and equivalents in civil law countries do indeed have a higher status than your common or garden notary public down at the library. But I don't know of any more worthy term in English, so I've been translating it Notary Public for 30 years. I think it conveys the sense well enough to the English-language reader.

Not "notary public"; that, in my opinion, would be a serious mistranslation. Why? Because as everyone here has already acknowledged, the expression "notary public" in English, specificaly American English, carries a precise meaning, and what it means is something quite different from a "notario público", a common law notary.

I will not pretend that I have studied the Costa Rican notary system in detail, but I am familiar with the Spanish system and have read enough to know that the system in Latin American countries is the same in material respects. One difference is that a civil law notary is called a "notario" in Spain and often a "notario público" in Latin America (including, as we can see, in Costa Rica). But they're the same thing.

Henry is absolutely right that to translate "notary public" as "notario" or "notario público" in Spanish would be highly misleading, and I'm interested to read what he says about Texas. But simple logic surely dictates that the converse is also true, and that to translate "notario público" as "notary public" would be equally misleading for the same reason. The only excuse for doing so is that it is a literal translation of the words, but that's not what translation is about.

The Wikipedia articles on this provide sufficient background info.:

http://es.wikipedia.org/wiki/Notario
http://en.wikipedia.org/wiki/Civil_law_notary
http://en.wikipedia.org/wiki/Notary_public

I admit that a common law notary public is sometimes referred to just as a "notary", but it's really the only word available. A notary is quite definitely not an attorney.

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Note added at 1 hr (2014-10-08 20:56:40 GMT)
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Sorry; I made a slip at the end of the first paragraph. I meant to say that a notary public is quite different from a "notario público", a civil law notary.

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Note added at 2 hrs (2014-10-08 21:36:55 GMT)
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Let me put it another way. "Notario público" means a civil law notary. The English word "notary" can mean either a civil law notary or a common law notary. Which it means is usually clear from the context, and that's obviously true here; in Costa Rica it can only refer to a civil law notary. But "notary public" is unambiguously a common law notary and cannot mean a civil law notary. So it cannot mean "notario público". It's an error, and a bad one. When errors are repeated people get accustomed to them, and lose sight of the fact that they are wrong. But custom doesn't make them right.

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Note added at 3 hrs (2014-10-08 22:29:40 GMT)
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I have to say I'm bemused by how this question has gone. I've said enough about why I don't think "notario público" should ever be translated as "notary public". But only in exceptional circumstances will you ever translate it as "civil law notary", even though that's what it is. You might do so if you're translating something about the difference between "notarios (públicos)" and notaries public, but normally you'll just put "notary".

Suppose you have to translate:
"Y yo, el notario público, doy fe que...".
I maintain that you should NOT put:
"And I, the notary public, hereby certify that...",
because he/she is not a notary public. But you're not going to put:
"And I, the civil-law notary, hereby certify that..."
It would be ridiculous, and it's certainly not done.
If you want to put "public notary", I suppose you could, though it doesn't add anything. In Spanish-speaking countries notaries are public officials by definition.

The debate is very informative. But the asker - in the US - should specify the target-readership as there is also a Commissioner for Oaths in the UK/Ireland and rest of the Brit. Commonwealth, including Canada, but not the US.

Also an English conveyancing and probate Solicitor acquaintance
of mine - with fluent French - calls him in France: Monsieur le Notaire and neither an avocat nor an avoué that is a label still used.

Although they are quite different from a notary in the USA whose qualifications are very slim. A Civil Law Notary such as in Costa Rica and all Spanish-speaking countries is a highly qualified attorney. "Notary Public" is the translation into English, but the other way around use "Fedatario" because to use "Notario Público" in Spanish for a US notary would be highly misleading and it is prohibited in some states such as Texas where I reside.

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Note added at 1 día19 horas (2014-10-10 15:03:13 GMT)
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I would add that in 43 years of practice including translation of large numbers of documents from Mexican notaries, no one has ever objected to or even commented on the equivalent "Notario Público > Notary Public".

Using it in the other direction is of course a no-no.