The main entrance to the cathedral is on the south side, about halfway down. Overall, the building is 85 m long, the nave is 55 m long and 22 m high, and the aisles are 11 m.
The sacrificial altar stands under the chancel arch (1997). This was a gift from the German episcopate and is the work of German artist Heinrich Bückner. The shape is reminiscent of an early 16th-century altar. The panels are made of gilded bronze and are adorned with religious scenes and figures. The frontal depicts the Risen Christ in the middle and scenes from the life of Jesus on the sides.
The late 17th-century baroque saint’s tomb in the presbytery was modelled on the tomb of St. Peter in the Vatican. It was renovated in 1997 after being removed by the Nazis. A silver coffin bearing the figure of St. Wojciech and containing his relics rests on a high pedestal under an ornate baldachin. Made in Gdańsk by Peter van der Rennen in 1662, the coffin depicts 10 scenes from the life of St. Wojciech on the lid and the sides. Parts of the coffin components were stolen in an audacious 1986 theft which left the figure of the saint and the bas reliefs seriously damaged. The thieves were arrested in Gdańsk and the stolen items recovered. The silver, however, had been melted down and the parts that had been destroyed were refashioned from it in 1987. The coffin is supported by figures representing the four conditions (Władysław Marcinkowski, 1897).
The former tomb of St. Wojciech, a red marble Gothic work by Gdańsk sculptor Hans Brandt c. 1480 and reconstructed 1997, is in the rear part of the presbytery, although it is best viewed from the pulpit.
The precious late-Gothic tombstones of Abp. Zbigniew Oleśnicki, a red marble work by Veit Stoss in 1495, and Abp. Jakub of Sienna (d. 1480), a bronze work by an anonymous Flemish artist, can be found under the matroneum in the western part of the nave.
The entrance to the cathedral basement is under the north tower. A cathedral guide is available for group tours. The basement was built in 1957-1964, following an archaeological examination that uncovered fragments of the first pre-Romanesque temples and ancient stone tombs under the floor. These have been partially reconstructed. There is a well preserved 11th-century Romanesque wall and a replica of a slab with an inscription dated 1006 (the oldest in Poland) in a crypt between the towers. The original is elsewhere in the basement but is not accessible. There is a fragment of a Pagan devotional fireplace (possibly 8th century) in the middle of the main crypt and relics of the first temples a little further east. The necropolis of the Gniezno archbishops is under the south aisle.