If you want to work as a freelancer in Spain, you'll usually need to register as an autónomo. One of the first tax steps is submitting Modelo 036 to the Agencia Tributaria (AEAT). This census declaration registers your business activity, tax obligations, and fiscal details. It's also the form you'll use to update or deregister your tax information throughout your self-employed journey.
TL;DR
- Modelo 036 is the tax registration form used to register as an autónomo with the Agencia Tributaria.
- You'll submit it before starting your activity and whenever your tax details change.
- The form tells the tax authorities what business activity you'll carry out and which taxes apply to you.
- Since 2025, Modelo 036 has replaced the old Modelo 037, making it the standard registration form for new autónomos.
- If you register through Xolo, we take care of the paperwork for you, so you don't have to navigate Modelo 036 yourself.
What is Modelo 036?
Modelo 036 is the official census declaration that registers you as a business or self-employed professional with Spain's tax authority.
Before you can legally invoice clients as an autónomo, you must notify the Agencia Tributaria that you're starting an economic activity. That's exactly what Modelo 036 does.
By submitting it, you register in the Censo de Empresarios, Profesionales y Retenedores (Business, Professional and Withholding Tax Census), allowing the tax authorities to identify your activity and determine which tax returns you'll need to file in the future.
Unlike quarterly tax returns such as Modelo 303 (IVA) or Modelo 130 (IRPF), Modelo 036 isn't filed on a recurring basis. It's only submitted when you need to register, update or deregister your tax information.
Who needs to submit Modelo 036?
Most people starting a self-employed business in Spain will need to submit Modelo 036 before beginning their activity.
This includes freelancers registering as autónomos, companies establishing operations in Spain, and other taxpayers who need to register with the Agencia Tributaria.
As an autónomo, you'll typically submit Modelo 036 if you're:
- registering your business for the first time
- starting a new professional or business activity
- changing your fiscal address
- updating your tax obligations
- registering for intra-EU transactions (ROI/VIES)
- deregistering when you stop your activity
💡 Takeaway: Modelo 036 isn't just for registering as an autónomo—it's the standard form used whenever your tax registration needs to be updated.
When do you need to file Modelo 036?
You'll normally file Modelo 036 before starting your activity and again whenever your registered tax details change.
There are three common situations where you'll use the form.
Registering as an autónomo
Before issuing your first invoice or starting your business activity, you'll need to register with the Agencia Tributaria using Modelo 036.
This officially informs the tax authorities that you're beginning a professional or business activity and establishes your tax obligations from day one.
Updating your tax details
If important information changes after you've registered, you'll need to notify the Agencia Tributaria.
Common examples include:
- changing your fiscal address
- adding or changing an economic activity
- changing your IVA regime
- registering or leaving the ROI (Register of Intra-Community Operators)
- updating other tax obligations
In most cases, changes should be reported within one month.
Deregistering your activity
If you stop working as an autónomo, you'll also use Modelo 036 to notify the tax authorities that your activity has ended.
This helps ensure you're no longer expected to submit tax returns after you've ceased trading.
👉 For a full run-down on how to deregister as an autónomo read our guide Autónomo Deregistration in Spain: How It Works.
What information does Modelo 036 include?
Modelo 036 collects the information the Agencia Tributaria needs to identify your business activity and determine your tax obligations.
Depending on your circumstances, you'll typically provide:
- your name and NIF (tax identification number)
- your fiscal address
- your business or professional activity
- the corresponding IAE activity code
- your IVA obligations and VAT regime
- your IRPF obligations
- whether you'll carry out intra-EU transactions (ROI/VIES)
- the date your activity begins
The exact information required depends on your business structure and the type of activity you'll carry out.
How do you submit Modelo 036?
Most autónomos submit Modelo 036 electronically through the Agencia Tributaria.
You can file the form online using one of the accepted identification methods, such as:
- Cl@ve
- Digital Certificate
- Electronic ID (DNIe)
The Agencia Tributaria also provides guided online filing tools for many straightforward registrations.
If you're using an online gestoría like Xolo, we'll prepare and submit the registration on your behalf, ensuring your tax setup matches your business from the start.
What happened to Modelo 037?
Modelo 037 no longer exists. Since 2025, all new registrations are made using Modelo 036.
Previously, some freelancers could choose between the full Modelo 036 and the simplified Modelo 037.
Following changes introduced by the Agencia Tributaria, Modelo 037 was discontinued, making Modelo 036 the standard registration form for new autónomos.
If you're reading guides that still recommend Modelo 037, they're no longer up to date.
Do you need Modelo 036 before registering with Social Security?
Yes. Registering with the Agencia Tributaria is one of the first steps before completing your autónomo registration with Social Security.
Starting a business as an autónomo usually involves two separate registrations:
- Registering your tax activity with the Agencia Tributaria using Modelo 036.
- Registering with Seguridad Social under the RETA (Special Regime for Self-Employed Workers).
Both registrations are required to operate legally as an autónomo in Spain.
Let Xolo handle your Modelo 036
Completing Modelo 036 yourself is entirely possible, but it's also one of the first opportunities to make mistakes that can affect your tax obligations later.
When you register as an autónomo with Xolo, we handle the registration process for you, including your tax registration with the Agencia Tributaria and your Social Security registration.
You'll also get:
- an English-speaking team that understands Spanish taxes
- online invoicing and bookkeeping tools
- ongoing support with IVA, IRPF and tax filings
- expert guidance whenever your business changes
That means you can spend less time navigating paperwork and more time focusing on growing your business.
FAQ
Is Modelo 036 mandatory for autónomos?
Yes. Most freelancers registering as autónomos will need to submit Modelo 036 to register their activity with the Agencia Tributaria.
Can I submit Modelo 036 online?
Yes. The form can usually be submitted electronically through the Agencia Tributaria using Cl@ve, a Digital Certificate or another accepted electronic identification method.
Is Modelo 036 the same as registering with Social Security?
No. Modelo 036 registers your tax activity with the Agencia Tributaria. You'll also need to register with Seguridad Social under RETA.
Do I need to submit Modelo 036 every year?
No. You only submit Modelo 036 when registering, updating your tax information or deregistering your activity.
What happens if my business details change?
If your fiscal address, business activity or tax obligations change, you'll normally need to notify the Agencia Tributaria by submitting an updated Modelo 036.
Does Xolo submit Modelo 036 for me?
Yes. When you register as an autónomo through Xolo, we handle your tax registration with the Agencia Tributaria as part of the onboarding process.