Tax, Accounting, and Labor Consulting Services for Self-Employed Individuals, SMEs, and Companies in Barcelona
We’re here for you with a clear, personalized service —no fine print—offering both online and in-person support in Barcelona.
Who is this agency for?
Self-employed
They want to comply with the tax authorities and Social Security without errors or wasting time.
SMEs
They need reliable accounting controls and efficient tax planning to grow.
Companies
They are looking for a stable team for their tax, accounting, and HR departments (without relying on a single person).
Entrepreneurs
They're going to sign up and want to start off on the right foot from day one.
What Our Administrative Services Include
Tax Management (Taxes and Obligations)
We handle the preparation and filing of your tax returns, including a preliminary review and assistance with any questions or requests. Depending on your situation, this may include, among other things:
VAT (periodic filing and summary, when applicable)
Income Tax (installment payments, if applicable)
Withholdings (if you have employees, independent contractors, or rental income)
Useful Note for Users (SEO + Authority):
Self-employed individuals and companies typically file forms such as Form 036 (census registration) and, during their business operations, VAT, personal income tax, and withholding tax forms depending on their circumstances. The Tax Agency regulates business registration through Form 036 and provides specific guidance (Censos WEB).
If you act as a withholding agent, the AEAT specifies obligations such as filing Form 190 if you filed Form 111, and Form 180 if you filed Form 115
Accounting and Financial Control
Recording and Accounting for Revenues and Expenses
Invoicing and Documentation Control (Organization and Traceability)
A basic overview of margins and earnings so you know “how your business is doing”
Preparation of information for year-end closings and advice on routine decisions
Human Resources Management (if you have employees)
Hiring and Terminations, Contracts, and Employment Documentation
Payroll, Social Security contributions, and tracking of recurring obligations
Support in the event of incidents and coordination with the legal team if a dispute arises
Registrations, changes, and all types of administrative procedures
We guide you through and handle the most sensitive procedures at the start of (and throughout) your business:
Registration with the Tax Authority (business registration/IAE) and proper tax setup
RETA (Social Security) Registration: This must be requested before starting the business and can be processed in advance (Import@ss).
Data Changes, Terminations, and Administrative Adjustments
Registering as a Self-Employed Worker in Barcelona and Catalonia: How We Do It
A poorly filed registration (business category, tax regime, withholdings, VAT, etc.) can cost you dearly in terms of time and penalties. That’s why, before we file your paperwork, we review your case and set everything up properly so it doesn’t “blow up in your face” in the first quarter.
Step 1 — Quick Diagnosis (No Technical Jargon)
We’ll ask you for 6–8 key pieces of information and outline your tax and Social Security plan.
Step 2 — Proper Registration (Tax Authority + RETA)
Registration with RETA must be completed before starting work, and Social Security allows you to process it in advance (Import@ss).
Step 3 — Start and First Quarter Under Control
We provide you with an invoicing checklist, a list of deductible expenses “at our discretion,” and a realistic timeline of obligations.
Local Government Supplement (Catalonia):
In Catalonia, Canal Empresa provides information on registering as a self-employed worker and notes that, at offices accredited as PAE points, registration can be processed immediately and simultaneously with Social Security, among other procedures.
Why Martínez Caballero Abogados
Joint team: administrative services + legal support in the event of issues
Clear communication: You know what’s coming, when, and why
Order and Control: Well-Structured Documentation from the Start
Real support: You’re not just a number—we’re here for you
What we'll need from you to get started
To get started right away, we usually ask for:
ID number (DNI/NIE) and contact information
Activity/service you will provide and estimated start date
If you have a store, employees, partners, or online sales
Invoices/Revenue and Expenses (if you’re already up and running)
Access/representation for online filing (as applicable)
Why Martínez Caballero Abogados
Joint team: administrative services + legal support when issues arise
Clear communication: You always know what's coming, when, and why
Order and Control: Well-Structured Documentation from the Very Beginning
Real support: You're not just a number—we follow up with you
Online and in-person administrative services in Barcelona: you choose how you want to work
At Martínez Caballero Abogados, we offer a unique administrative service that is flexible and tailored to your way of working. Our extensive experience has taught us that not all self-employed individuals, small and medium-sized businesses, and companies have the same needs or work at the same pace, so we provide a hybrid service tailored to your specific needs.
We combine online administrative services with in-person assistance at our Barcelona office if you prefer face-to-face strategic meetings and direct interaction when dealing with more complex matters.
Online: documentation and support without having to travel—ideal if you’re working on a tight schedule.
In-person in Barcelona: strategic meetings, complex cases, or whenever you prefer face-to-face interaction.
Frequently Asked Questions About Our Administrative Services for Self-Employed Individuals and Small Businesses
What exactly does the administrative service for self-employed individuals include?
Our accounting services for self-employed professionals include tax management (filing periodic tax returns based on your business activity), organizing and reviewing accounting records, ongoing advice, monitoring administrative obligations, and assistance with routine communications from the IRS or Social Security. In addition, we guide you on proper invoicing, deductions, and planning to avoid mistakes that could result in penalties.
Do you also offer accounting services for small and medium-sized businesses and companies?
Yes. In fact, it’s a good idea to seek advice before registering your business. We’ll help you properly register with the tax authorities and Social Security, choosing the appropriate tax structure based on your business activity to avoid problems in the first quarter.
Can I hire an accounting firm even if I'm not yet registered as self-employed?
Yes. In fact, it’s a good idea to seek advice before registering your business. We’ll help you properly register with the tax authorities and Social Security, choosing the appropriate tax structure based on your business activity to avoid problems in the first quarter.
Is the agency 100% online, or do I need to go to the office?
We offer both options. You can send us your documents electronically and receive remote consultation, or visit our office in Barcelona if you prefer in-person meetings. Many clients combine both options depending on their needs.
What happens if the IRS sends me a demand for payment?
If you receive an administrative notice or request, we will analyze its content, review your situation, and help you prepare a response within the established deadline. Our goal is to minimize risks and ensure that the documentation submitted is accurate and consistent with your accounting records.
How much does an accounting firm charge for self-employed individuals?
The cost depends on your volume of business, the number of invoices, whether you have employees, and the type of tax obligations you must fulfill. After analyzing your situation, we’ll provide you with a clear proposal outlining the services included, ensuring there are no surprises or hidden costs.
What documents do I need to provide to get started?
We will generally need your DNI/NIE, contact information, details about your business, invoices issued and received (if you are already in operation), and access to submit online applications on your behalf when necessary. We will let you know exactly which documents to provide based on your specific situation.
Do you also handle HR management if I have employees?
Yes. If you have employees, we can handle your HR administration: contracts, hiring and terminations, payroll, and Social Security obligations. This allows you to centralize tax, accounting, and HR management within a single team, making it easier to monitor and coordinate these processes.
Can I switch accounting firms if I already have one?
Yes. Switching accounting firms is a common process. We can help you coordinate the transition by requesting the necessary documentation to ensure continuity in accounting and tax matters, without interruptions or errors in future filings.
What are the benefits of working with an accounting firm that specializes in self-employed individuals and small and medium-sized businesses?
A specialized accounting firm understands the unique needs of the self-employed and small businesses: common tax deductions, planning for estimated tax payments, managing withholding taxes, and tax optimization within the law. This allows businesses to anticipate problems, improve their financial organization, and avoid penalties for procedural errors.
Hire a lawyer to provide legal advice
Pay online quickly and easily, get a consultation with the best attorney for your specific case, follow the steps, and we’ll contact you as soon as possible to schedule the date and time of your consultation, whether online or in person.
