The Constitution provides that Deputies are representatives of the Nation and they are not bound by any instructions of their electorate, which conforms to the rule of the so-called free mandate. The free mandate implies that the Deputies represent the subject of sovereignty (i.e. the Nation), and not the particular social groups and that they can not be removed by the electorate or the legislator. The Constitution provides for the possibility to deprive a Deputy of his mandate by the Tribunal of State if the former, acting contrary to the constitutional prohibition, performs any business activity involving any benefit derived from the property of the State Treasury or local self-government or acquires such property. Moreover, the mandate expires in the following instances: the refusal to take the oath, the deprivation of the eligibility to be elected, the relinquishment of the mandate, the making of a false statement as regards the matters enlisted in the act on the disclosure of employment in or service for the organs of State security or cooperation with them in the years 1944-1990, the occupation of an official position in the State organs or the appointment to such position, the performance of which is incompatible with the discharge of the mandate according to the constitutional understanding of the incompatibilitas principle. The Constitution only allows the Deputy to perform the functions of member of the Council of Ministers or of secretary of State in the governmental administration.

The institution of immunity provides the protection of the independence of Deputies and the Sejm ensures the free discharge of all duties connected with the mandate. According to the provisions of the Constitution, a Deputy may not be held accountable for his activity performed within the scope of his mandate during the term thereof nor after its completion. Deputy can only be held accountable before the Sejm; however, in a case where he has infringed the rights of third parties (the infringement of personal rights), he may be proceeded against before a court only with the consent of the Sejm. Furthermore, the Constitution states that a Deputy shall not be subjected to criminal accountability from the day of announcement of the results of the elections until the day of expiry of the mandate. The immunity may be annulled as a result of the concerned Deputy's consent or on the basis of a resolution of the Sejm. A Deputy may neither be arrested nor detained without the consent of the Sejm, except for cases when he has been apprehended for the commission of an offence and in which his detention is necessary for securing the proper course of proceedings. Any such detention shall be immediately communicated to the Marshall of the Sejm, who may order the immediate release of the Deputy.

The rights and duties of the parliamentary representatives are described in detail by the provisions of the Act on the Exercise of the Mandate of a Deputy or Senator as well as by the provisions of the Standing Orders of the Sejm. Those rights and duties can be divided into two groups:

1. those related to the activities of the Chamber: the right and obligation to participate in the workings of the Sejm and the committees, the right to present interpellations and questions as well as questions on current issues, the right to organize clubs, groups and Deputies' groupings and the right to stand for elections to the Sejm's organs and to sit in those organs,
2. those related to the discharge of the duties connected to the mandate: the right to organize a constituency office, the duty to inform the electorate about the workings of the Sejm, the right to obtain information and explanations from members of Council of Ministers and from State or self-government organs and institutions in relation to matters which result from the discharge of the Deputy's duties, the right to intervene in organs of State and local self-government administration, state-owned establishments and enterprises, social organisations, as well as in commercial units which do not belong to the State.

Moreover, Deputies are obliged to submit declarations as to the state of their personal property (immediately after the elections, subsequently once a year and two months before the date of the next election). The benefits obtained by Deputies during their term of office are recorded in a Registry of benefits which is open to the public.