Stable Union in Brazil: How to Prove It, Register It, and Protect the Couple and Their Property

This page is a translation of the original Portuguese text, provided for convenience. It deals with Brazilian law. If there is any discrepancy, the Portuguese version prevails. Read the original in Portuguese

Brazilian law recognizes the stable union (união estável) as a family unit, with property and inheritance effects close to those of marriage, but its existence depends on proof. Knowing what defines it, how to document it, and what a cohabitation agreement does can help you avoid disputes over dividing property and inheritance.

What defines a stable union

Article 1.723 of the Civil Code defines a stable union as a relationship between two people that is public, continuous, and lasting, and that is entered into with the goal of forming a family. The law sets no minimum period. A relationship of just a few months can qualify as a stable union, while a years-long dating relationship may not, if the purpose of forming a family is missing.

The most important requirement is what the law calls the intention to build a life together. Living under the same roof is not mandatory, although cohabitation is strong evidence. What the legal system looks at is how the couple appears to others as a family: they present themselves socially as one, combine their assets, take on shared responsibilities, and plan a future together.

The public requirement rules out hidden or clandestine relationships. Continuity requires stability, not occasional meetings. Durability shows that the bond has solidified over time. When all of these elements are present, the stable union comes into being automatically, whether or not it is registered. That brings both protection and uncertainty when documentation is lacking.

How to prove a stable union

The most widely accepted forms of proof include a declaration recorded at a notary’s office (cartório), joint bank accounts, proof of residence at the same address, photographs from family events, listing each other as dependents on health plans, pension plans, or income tax returns, and mail addressed to the couple. Children in common also carry significant weight, although they are not essential.

Witness testimony supplements documentary evidence. Neighbors, relatives, and friends can confirm that the couple lived together openly and treated each other as family. The sooner a couple organizes this documentation, the lower the risk that the relationship will be challenged just when one partner can no longer speak for himself or herself.

In practice, we recommend gathering and keeping these records throughout the relationship, not on the eve of a dispute. Reconstructing the evidence later is possible, but it is costly and open to challenge by the other party or by heirs.

A relationship of just a few months can qualify as a stable union, while a years-long dating relationship may not, if the purpose of forming a family is missing.

The cohabitation agreement and the property regime

When the partners have not agreed on anything, the partial community property regime (comunhão parcial de bens) applies to the stable union under Article 1.725 of the Civil Code. Under this regime, everything acquired for value during the relationship becomes part of the shared estate. It is divided equally on separation or death, regardless of who paid for it.

A cohabitation agreement (contrato de convivência) lets the couple opt out of this default regime. Through it, they can choose complete separation of property, universal community property, or customized rules for managing their assets. The agreement gives security to a partner who enters the relationship with existing assets, runs a business, or wants to protect property from a possible dispute.

The agreement can be made by public deed at a notary’s office or by private instrument. A public deed is the safest and most recommended form, especially when real estate is involved, because it makes registration easier and reduces challenges. The document should state the date the relationship began, a sensitive point in determining which assets are subject to division.

One effect is often overlooked: the agreement governs property, but it does not create or end a stable union on its own. The union exists even without an agreement, and simply signing an agreement is not enough to create a family unit if the factual requirements are missing.

Inheritance rights of the partner

The partner’s position in inheritance law has changed profoundly. In judging Theme 809 (RE 878.694), the Supremo Tribunal Federal (Brazil’s Supreme Federal Court) declared unconstitutional the different treatment that Article 1.790 of the Civil Code gave to stable unions. As a result, the partner now inherits on the same terms that Article 1.829 provides for a spouse.

In practice, the surviving partner shares the estate with descendants and ascendants depending on the property regime adopted and, in their absence, receives the entire estate. This equal treatment makes it even more important to choose the property regime carefully, since it directly affects how much the partner receives, both as a share of the community property and as an inheritance.

Two concepts that are often confused need to be kept apart. The meação (the partner’s half of the shared property) is the half of the common estate that already belongs to the partner by virtue of the property regime, and it is not an inheritance. The inheritance is drawn from the deceased person’s share. The partner can therefore receive his or her meação and also share in the inheritance.

Given this complexity, planning your succession during your lifetime, through a will or by organizing your assets, helps avoid disputes between the surviving partner and the other heirs, especially in families with children from earlier relationships.

Converting a stable union into marriage

Article 1.726 of the Civil Code gives partners the right to convert a stable union into marriage. Conversion preserves the history of the relationship and makes the bond easier to prove. It gives you the formal security of married status without requiring a new ceremony in the traditional sense.

The procedure is carried out directly at the civil registry office (cartório de registro civil). The partners file the request, submit the required personal documents, and state the property regime that will apply going forward. After the marriage application is approved, the marriage record is drawn up, and for purposes of proof, the effective date usually reaches back to the start of the relationship.

Conversion appeals to those who want to remove any doubt about the existence of the bond, make transactions such as financing and inheritance easier, and publicly establish their marital status. Even so, the decision should take into account the property regime chosen, since it will govern how property is divided from then on.

Frequently Asked Questions

Do you have to live together to have a stable union?

No. Living under the same roof is strong evidence, but it is not a legal requirement. What the law requires is a public, continuous, and lasting relationship with the goal of forming a family. Couples who keep separate homes but live their lives as a family can have a stable union recognized, as long as they can show other convincing evidence.

Does a cohabitation agreement have to be made at a notary’s office?

It is not mandatory, since the agreement can be made by private instrument. A public deed at a notary’s office is nevertheless the safest form, especially when real estate or significant assets are involved, because it gives the document greater evidentiary weight and makes future registrations easier. The choice of property regime must be stated expressly in the document.

Does a partner have the same inheritance rights as a spouse?

Yes, following the Supremo Tribunal Federal’s decision that eliminated the different treatment. Today a partner inherits on the same terms as a spouse, sharing the estate with descendants and ascendants depending on the property regime and receiving the entire estate in their absence. That is why choosing a property regime and planning your succession during your lifetime are so important for couples.

As informações deste artigo são de caráter informativo e não substituem consulta jurídica individualizada. Cada caso possui particularidades que exigem análise específica.