Guide
How a CUIJ is read and how an Argentine case file is checked
What the CUIJ is, why it is written in two different forms depending on the jurisdiction, what each group of digits means, how a case file is checked with no password or sign-up, and what the public lookup returns.
Open the official CUIJ lookupLook up your case nowWhat the Argentine courts publish, and where
There is no single portal. Each jurisdiction publishes its own lookup, and only some open it without a password: the courts of the City of Buenos Aires publish theirs on the City's judicial case file system, and the judiciaries of Catamarca, Mendoza and Salta publish theirs on a case management system they share.
Those four are checked with no account, no password and no identification. The rest of the country splits the task across twenty different systems, and several ask for a password, a bar number or a prior verification. That is why no tool covers the whole country: there is no one door, there are twenty-four.
What is common is the number. An Argentine case file is identified by a CUIJ, and learning to read it is useful in any jurisdiction — although, as you will see in a moment, it is not written the same way everywhere.
How a CUIJ is read
The CUIJ is the case file's unique identifier, and it has two ways of being written depending on the jurisdiction. It is the same number: what changes is which parts are written down.
Long form (City of Buenos Aires and Catamarca)
L-JJ-NNNNNNNN-V/AAAA-S
Short form (Mendoza and Salta)
JJ-NNNNNNNN-V
The jurisdiction code
The two digits after the letter, or the first two in the short form. They identify the jurisdiction and follow the alphabetical order of the provincial codes of Ley 22.202: 01 is the City of Buenos Aires, 03 Catamarca, 13 Mendoza and 17 Salta. They are not the instance, which is the most common misreading of the number, and they are not the statistics bureau's codes either, which say something else for the same four jurisdictions.
The case number
Eight digits, the running number the jurisdiction assigned to the case. It is the one most often written down wrong when dictated over the phone, and the one most worth copying and pasting.
The check digit
A single digit at the end of the block, and it is not decorative: the service validates it. A CUIJ with the check digit changed does not return a different case file, it returns none — and that answer is identical to the one for a case file that does not exist.
The letter, the year and the suffix
Long form only. The letter is transcribed as printed — two have been measured, J and N, and what tells them apart is not published: it is not the court, because in Catamarca a civil file and a commercial one both carry the J. The year is the one the case was registered in, and the suffix tells side proceedings apart from the main file. In Mendoza and Salta the number carries none of the three: asking for them there is looking for something that does not exist.
Hence the practical rule: copy the CUIJ exactly as the jurisdiction hearing the case prints it, and do not translate one province's format into another's. A City or Catamarca number written in short form, or a Mendoza one with a year and suffix bolted on, finds nothing.
Five steps to check a case file
The order matters, above all the first one: opening the wrong portal is the most common waste of time here.
Find out which jurisdiction is hearing it
There is no national search. The case file is checked on its own jurisdiction's portal, and the CUIJ's jurisdiction code tells you which: 01 is the City of Buenos Aires, 03 Catamarca, 13 Mendoza and 17 Salta.
Open that jurisdiction's public lookup
In the four that publish it openly you need no account, no password and no bar number: it is in plain view. In the rest of the country public access is more restricted and is worth checking before you try.
Write the CUIJ in that jurisdiction's form
Long in the City of Buenos Aires and Catamarca, short in Mendoza and Salta, with the check digit exactly as printed. One digit changed returns exactly the same empty answer as a case file that does not exist, so the mistake does not look like a mistake.
Read the case title and the court
The case title says who is claiming against whom and over what; the court of record says where the file sits today. That changes over the life of the case, and it is worth reading before the list of filings.
Go through the filings
Each one carries its date and its type, oldest to newest. Some also carry the text of the ruling; others are only the record of a movement and have no text to show.
Look up your case here
Custodio asks the court portal for you, so it can take a few seconds. We ask you for no name, no email and no account: what the lookup leaves behind is a single record, deleted two hours later. How we handle this lookup
The Argentine lookup reads case files from the local courts of the Autonomous City of Buenos Aires, Catamarca, Mendoza and Salta.
This video is narrated in Spanish only; the transcript below is in English.
The video was recorded on the Uruguay guide; on this guide the steps are the same, with this country’s case number and portal.
Read the video transcript
This guide explains how to look up a case file at the Judiciary of Uruguay. First, the site asks about cookies: choose what you prefer.
Inside the guide there is a search box. Type the case number in the format the country uses; here we use a sample case file.
Custodio checks that a person is making the lookup before it goes out to ask. It does not ask for an email or a password, and it does not keep the number you typed.
Look it up. Custodio asks the court portal on your behalf, so it can take a few seconds.
This is what the portal publishes today: the court, the parties and the latest action with its date. The parties appear as initials, because nobody has identified themselves here yet.
At the bottom it says how far this country's lookup reaches. Read it before drawing conclusions: the Uruguayan lookup runs one business day behind and does not cover criminal matters.
Looking once is looking once. With a free account you can put that case file under watch: Custodio checks the portal every day for you and alerts you when a new action appears.
What the lookup returns
Six pieces of data, and none of them is an interpretation: they are the fields the system itself publishes.
- The case title: who is claiming against whom, and over what.
- The CUIJ and the type of case file, as the jurisdiction recorded them.
- The court the case file sits in today, with its full name.
- The file's administrative status: in progress, archived and whatever else the jurisdiction uses.
- The list of filings, with the date and type of each one.
- The text of the ruling, for the filings that carry it.
Paste your CUIJ and we'll flag every new move
We watch the case file for you in its own jurisdiction: an alert the moment there is a new movement, no more checking by hand. With each one, the AI updates the matter status and proposes the deadline that runs; it drafts the reply when you ask.
Create your free accountWhat the official lookup does not do
Saying so saves half an hour looking for something that is not there, and explains why tools exist that work on top of this channel.
- It is not national. Each jurisdiction publishes its own and no index joins them, so a caseload spread across provinces is checked portal by portal.
- It does not notify. It answers what is there at the moment you ask: to find out something moved you have to ask again, case file by case file and day by day.
- The open search is capped. In several jurisdictions an unfiltered search returns at most a thousand results, and that number is the cap on the answer, not the size of the archive.
- Not the whole archive is online. An old case file may not show up, and the answer is the same as for a mistyped number: check the CUIJ before concluding the matter does not exist.
- Open coverage changes without notice. A jurisdiction publishing its lookup today can close it tomorrow, and that has happened: a province that used the same system as Mendoza and Salta until 2025 took it down.
None of this is fixed by checking more often: they are properties of the channel, not failures of whoever is checking.
Frequently asked questions
Does checking a case file cost anything?
No, in the jurisdictions that publish the lookup openly: it is public and free, and asks for no sign-up and no identification of any kind.
Do you have to be a lawyer or hold a bar number?
No, in those same jurisdictions: anyone with the CUIJ can check the case file. The exception is a file the jurisdiction marks as private, which is shown to nobody through this channel.
Why does a colleague's CUIJ have more parts than mine?
Because it is not written the same way in every jurisdiction. The long form, with a letter, year and suffix, is the City of Buenos Aires and Catamarca one; Mendoza and Salta use the short one. It is the same identifier written differently, not two separate numbering schemes.
Is the court shown the one that will decide?
It is where the case file sits today, which is not always where it started or where it will end: with appeals or a change of venue the file moves from one court to another, and the lookup always shows the current one.
Can I look it up from here?
Yes, for case files of the local courts of the Autonomous City of Buenos Aires, Catamarca, Mendoza and Salta. This page has a lookup: paste the CUIJ and we query that jurisdiction's portal for you, with no account and at no cost. You will see the court, the latest action with its date and the parties reduced to initials; the whole case file is read in the official lookup this guide links to, or inside your account. And if you want us to tell you the day the case moves, you create a free account from the result.
Checking is the first step, not the work
Custodio looks up your case files every day and uses artificial intelligence on what it finds: case status, facts, drafts and answers over your documents, with the citation next to them.