Usually, laws are enacted following a proposal made by the Government, in which case the initial text is called a projecte de llei or Government bill. They can also come from a proposal made by a Parliamentary group or a group of Parliamentary members, in which case the initial text is called a proposició de llei or member's bill. This name is also given to texts resulting from citizens' initiatives, consells comarcals (county councils) and municipalities. If the Presiding Committee considers that a member's bill may lead to an increase in credit or a reduction in income, it must request the prior consent of the Government for the bill to be introduced. The Government's response must be justified and must be made within eight days of receiving the bill.

The procedure for a Government bill and a member's bill is very similar. Once published in the Butlletí Oficial del Parlament de Catalunya (official bulletin of the Parliament of Catalonia) and passed on to the corresponding committee, Parliamentary groups and Members of Parliament have a period usually lasting fifteen days during which they may lodge esmenes a la totalitat or amendments of the bill as a whole. After this stage, the process is as follows:

1. The Plenary Assembly debates the bill as a whole. Members discuss their overall view of the bill, the principles and criteria behind the proposal and, where applicable, amendments. They may propose to reject a bill (esmena de rebuig) or to return it to its sponsors (esmena de retorn), or propose an alternative text which, if passed, becomes the text used in the next stage of the bill.
2. Once the bill as a whole has been debated, so long as the process is the result of a legislative initiative, Parliamentary groups may propose, within the next five days, that stakeholding organisations affected by the legislation, including social organisations, be invited to speak in Parliament. The committee is responsible for agreeing to and arranging the visit of such organisations to Parliament.
3. Once such organisations have been invited, or the period for inviting them has ended, Members of Parliament and Parliamentary groups have up to fifteen days to lodge amendments to the proposed legislation.
4. The committee then appoints a sub-committee, which may consist of just one Member, various Members, or of a representative from each Parliamentary group. The sub-committee then appoints a reporter. The sub-committee drafts a report, assessing and considering the initial project and the amendments lodged. That reporter is tasked with co-ordinating the work of the sub-committee and acting as its spokesperson when the committee debates the report.
5. The Committee prepares a final report, which often entails rewriting the original text and incorporating those amendments that have obtained the support of the majority of Members.
6. Finally, the final report is debated by the Plenary Assembly, in which the Parliamentary groups and Members have another opportunity to defend the amendments lodged that have failed to obtain the support of the committee. The debate in the Plenary Assembly serves basically to give the Bill its final reading and for the positions of the groups and Members to be made public. Though infrequent, the Plenary Assembly may on occasions finally back an amendment.

In addition to the ordinary procedure, the Parliamentary Rules of Procedure also establish special procedures for:

• - bills for the basic development of the Statute, which must be passed by absolute majority.
• - budget bills.
• - reform of the Statute, which must be passed by a two-thirds majority.
• - the passing of legislation by committees in full legislative authority, that is, when the Committee is delegated to act on behalf of the Plenary Assembly in the taking of final decisions.
• - single readings, when a Bill is passed after a single vote and no amendments may be lodged, an exceptional procedure only used when the nature of the bill makes this advisable or the way the bill is formulated makes this possible.