The Sejm considers bills in the course of three readings (stages of procedure). The first reading takes place during the sitting of the Chamber (as a rule, this principle applies to the more significant bills) or at a sitting of a committee, and consists of the presentation of the justification by the mover, a subsequent exchange of questions and answers between the mover and the Deputies and a debate on the general assumptions of the bill. The first reading, which takes place during a sitting of the Sejm, may end with the rejection of the whole bill; usually, the bill is delegated to a committee (sometimes to one or even more, or to a special committee).

Further work on the bill is usually performed in sub-committees, with the participation of experts and representatives of the government. This stage of the legislative procedure ends either with the committee's acceptance of the bill which may contain a recommendation to adopt it with or without further amendments, or with a motion to reject the bill.

The movers of the amendments which were rejected by the committee may demand that their proposals be included in a report in the form of minority motions. The committees are independent as regards the direction of their work. However, the Deputies usually observe their political priorities. A times, the bill undergoes significant changes during this stage.