ASBL and AISBL are two forms of non-profit association. However, the constitution, structure and organisation of such associations are by no means the same and are often unknown to the founding members. Belgium has two forms of non-profit association: the non-profit association (ASBL) and the International Non-profit Association (AISBL).

Although ASBL is the most widely used form of association, AISBL proved to be less expensive than ASBL. In fact, the AISBL has many advantages that are not reflected by the ASBL.

• The AISBL has an international character, brought about by the international nature of its purpose. In practice, this means that the achievement of its purpose must be potentially useful outside Belgian territory;
• The AISBL is recognized by the Royal Decree, which strengthens its image in the minds of third parties. An ASBL cannot enjoy this kind of recognition;

• The AISBL is less bound by legal rules, which means that the founders have more freedom in defining the content of the statutes. Practical examples would be: 

1. the functioning of the AISBL bodies: while an ASBL has well-defined bodies, such as a general meeting and a board of directors with at least three directors (or two if there are only three members) and specific powers conferred, an AISBL has two mandatory bodies with only some specific powers and more flexibility in their operation and organisation;
2. Membership rights and obligations are not defined for AISBL.

• The requirements for the incorporation of AISBL are more simplified: in fact, an AISBL requires only a minimum of two founding members in contrast to the three mandatory founding members for an ASBL;
• If an AISBL wishes to change its registered office, it may, if the statutes so provide, proceed by decision of the management and is not required to convene the general meeting. On the other hand, the SBAL must convene the general meeting and amend its statutes.

However, some requirements are more complicated for an AISBL than for an ASBL.

1. The constitution of an AISBL must be done by notarial deed: the notary will submit to the approval of the Ministry of Justice the purpose of the association. On the contrary, ASBL may choose to incorporate the association by private contract, which may substantially reduce the costs of setting up;
2. The procedure for approving and publishing the Royal Decree may take some time. From a practical point of view, this can take up to three months;
3. The legal personality of an AISBL is granted on the day of the Royal Decree, while for an ASBL it is the day of deposit at the commercial court.

On balance, the AISBL has wider potential for founders wishing to have a non-profit association with a flexible international structure.