Delftse Poort (English: Delft Gate Building) is a twin-tower skyscraper complex at Weena 505 next to the Rotterdam Centraal railway station in Rotterdam, Netherlands. Tower I is 151.35 m (496.6 ft) with 41 stories, and Tower II is 93 m (305 ft) with 25 stories. Until May 2009, Tower I was the tallest office tower in the Netherlands. Both towers are built over a 4-storey multifunctional podium which adjoins the Rotterdam central station. The entire complex has 28 elevators. The gross floor area in the complex is 106,000 m² (1,140,000 sq ft), and the offices occupy 66,000 m² (710,000 sq ft).

It was constructed between 1988 and 1991. The cost of the construction was 240 million Dutch guilders, or about €110 million. Due to a metro tunnel running underneath the complex, advanced construction methods were required, allowing only a single underground floor to be built. The building is also known as Nationale-Nederlanden building, because until 2015 the Dutch Company 'Nationale-Nederlanden' (National-Netherlands) was the main user of the building.^[5] Nationale-Nederlanden was the local insurance branch of ING Insurance until 2014. In April 2015, the building was officially reopened by owner CBRE Global Investors as a general-purpose office building with 65,000 m² (700,000 sq ft) of office space.^[6] Nationale-Nederlanden became a tenant renting only a third of the building complex, and hence their logo on Tower I was removed.^[5][7] Since then the building has established its own identity, displaying its own logo on Tower I.^[5]

Until 2004, an annual race up the building's stairs took place in this building.