The Hooglandse kerk is an unfinished Gothic church with a few remnants of its Romanesque predecessor. It can be clearly seen that the nave was not nearly completed.

The Gothic Pieterskerk is a good example of the mixture of Brabantine Gothicism and local common sense, as found in many cities along Holland's coast. To prevent the building from sinking in the moist soil the building is unusually wide and has a wooden ceiling instead of stone vaults. Construction of this church was started in 1390. A 130 metres tall tower collapsed in 1512 and was not rebuild. The church came in protestant hands in 1570, but is no longer used as a church. Inside are the graves of many famous people, including that of painter Jan Steen.

This former chapel became the Academy or the university's main building in 1581.

The Marekerk was the first church in the province of Holland specifically built for protestant services, although it's not the first one that was actually finished. Construction lasted from 1638 until 1649. It's an octagonal centralized building with a tall, distinctive dome and a pseudo-classical entrance. Architect was Arent van 's Gravensande.

The Walloon church is the fomer chapel of a home for the elderly which had existed here since the 13th century. The chapel has been a protestant church since the early 17th century, and came in the hands of the Walloon community in 1818.

The exact origins of the St. Lodewijkskerk are unclear. It may have been built in either 1477 or 1538 as the chapel of a hospital. After 1567 it served several profane purposes, including that of an inspection-hall for the cloth-industry, but was returned to the catholic community in 1808, by order of king Lodewijk Napoleon. The wooden segment on top of the tower dates from 1588 and was intended for one of the towers of the town-walls, but was placed here in 1593.

In the 17th and 18th centuries many Eastern European jews settled in Leiden. This former synagogue dates from the mid-18th century.

The Hartebrug Kerk from 1836 is a Roman Catholic church in Neo-Classical or Waterstaat-style by architect Th. Molkenboer.

The St. Petruskerk dates from 1936 and is a typical example of the style of A.J. Kropholler. The church is at the centre of a small neigbourhood, the houses of which were designed by the same architect.