The current Landtag building stands in the eastern part of the Hafen district, on the Rhine just south of the Altstadt and the slim Rheinturm television tower. It opened in 1988, replacing the Standehaus across town, which had served as parliament from 1949 until then and is now part of the K21 art museum. The shape of the building is the part most visitors remember: the plenary chamber is a near-perfect circle, an architectural argument that representatives face each other rather than confronting a stage. Around 200 members sit there during legislative sessions. The state has roughly 18.1 million residents, about 13.2 million of them eligible to vote, which gives this parliament responsibility for more people than most European countries.

Legislation can be proposed by the government, by a parliamentary group, or by any seven members acting together, though in practice most bills come from the government. A proposal gets read and debated in the plenary chamber, then sent to one or more specialist committees that interview experts and lobby groups, then returned for a second reading and a vote on each amendment. Bills pass by simple majority, with a quorum of half the members present. Constitutional amendments and the state budget require three readings instead of two. Once passed, the president of parliament hands the law to the Minister-President, who signs and publishes it in the state's official Law and Ordinance Record.

The state is divided into 128 electoral districts, each containing roughly 140,000 residents. Each voter casts two votes: a first vote for a direct candidate in their district, a second vote for a party list. Parliament has at least 181 seats — 128 from the direct races and 53 from the lists — but the number expands with overhang and leveling seats to keep the totals proportional. North Rhine-Westphalia has the highest share of directly elected members of any German state, about 70 percent, compared with around 50 percent in most other Landtage and in the Bundestag. The 5 percent threshold applies. The current government, in office since June 2022, is a coalition of the CDU and the Greens supporting Minister-President Hendrik Wüst, re-elected after the 15 May 2022 state election.

The Minister-President is elected by parliament from its own ranks in a secret ballot — historically a formality, with only two exceptions: Franz Meyers in 1966 and Hannelore Kraft in 2010, both of whom needed a second round. Kraft's election was historic in another way: she was the first woman to lead the state government. Parliament can also remove a Minister-President by a vote of no confidence, which has happened twice, on 20 February 1956 and 8 December 1966. The Landtag elects four of the seven judges of the state Constitutional Court to staggered six-year terms, and it elects the state's delegates to the federal body that chooses the German president. Its powers have shrunk in recent decades as Berlin and Brussels have absorbed more authority, but on education, policing, and municipal law its word remains close to final.