Committees play a vital role in the activities of the Sejm. The Constitution provides for the existence of standing committees, i.e. those which function throughout the term of office, as well as for special and investigative committees (organised to examine a particular issue). According to the provisions of the rules of procedure (i.e. the Standing Orders) of the Sejm, the main function of the committees is to examine and prepare issues which are currently the object of parliamentary debates and to deliver opinions on matters which have been referred to them by the Sejm, the Marshal or the Presidium. Within the range determined by the Constitution and statutes, the committees also work as organs of parliamentary control .

The existing standing committees of the Sejm include those which deal with select issues (e.g. Committee for Liaison with Poles Abroad, Local Self-Government and Regional Policy Committee, European Committee); the range of the duties of other committees corresponds to the activities of particular ministries (e.g. Foreign Affairs Committee, Health Committee), while the activity of still others is closely related to the realisation of the respective competence of the Sejm (e.g. Constitutional Accountability Committee, Rules and Deputies' Affairs Committee, Deputies' Ethics Committee).

Particular tasks are assigned to the Legislative Committee. It participates in proceedings in relation to bills and draft resolutions, deals with problems of legislation and legal cohesion, and also cooperates in the organisation of the legislative process. It involves itself in matters related to proceedings before the Constitutional Tribunal and resulting from judgements of the Constitutional Tribunal, and also takes part in the supervision of implementation of laws and resolutions of the Sejm.

If a bill has not been referred to the Legislative Committee, the presidium of that committee may designate representatives who may participate in the sittings of the committees to which the bill was referred, but with no right to vote. Their proposals concerning the bill (draft resolution) introduced but not accepted by the appropriate committees, may be submitted by one of the above mentioned Deputies, at the Sejm sitting in the course of the second reading who will speak after the Rapporteur.

Special committees are those, whose existence was not provided for in the rules of procedures of the Sejm. They are established by the Chamber for a concrete purpose, whenever there is a need to deal with a particular problem (e.g. for the preparation of a bill).

According to the Constitution, the Sejm is also authorised to call an investigative committee to examine a particular issue, vested with special powers. The rules of the functioning of the investigative committee are defined by statute.

The composition of the committee is determined by the Sejm by means of a resolution, on the motion of the Presidium of the Sejm, after having obtained the opinion of the Council of Seniors. As a result, the composition of the committees reflects the political structure of the Chamber.