55 ハドソン・ヤード（英語：55 Hudson Yards）は、アメリカ合衆国のニューヨーク州ニューヨーク市マンハッタン区、ハドソン・ヤードにある超高層ビルである。ハドソン・ヤード再開発地区のすぐ隣に位置する。元々の名称、ワン ハドソン・ヤードやワン ハドソン・ブルバードとしても知られている。 

現在 55 ハドソン・ヤード が建っている場所は、元々はワールドプロダクトセンターの建設予定地だった。そこで、55 ハドソン・ヤードとワールドプロダクトセンターの両方の建設が計画されたが、プロジェクトの責任者がExtell Development Companyとのテナント契約から撤退し、ワールドプロダクトセンターの計画は無くなった。また、55 ハドソン・ヤードは完成した年の4月の内に最初のテナントによって占有された。

 ワールドプロダクトセンターの計画 
The "World Product Center" was a cancelled project that would have been among the world's first permanent healthcare marketplaces and education centers, serving commercial and educational needs of healthcare suppliers and providers. The project featured a tall tower designed by Gary Barnett with up to of office space proposed.

The project would have allowed healthcare professionals, students, and researchers to interact with the general public, with an expected 2 million visitors annually. The proposed building included a fully digitized auditorium, conference and educational facilities, media centers, traditional office space, a medical lab, healthcare facilities, and a Consumer Health Pavilion. The Pavilion would have offered the general public guided tours, interactive forums, and information about health literacy and healthcare careers. The World Product Center would have hosted trade shows and other events featuring medical device manufacturers, pharmaceutical companies, and healthcare associations to support healthcare commerce. These events would have showcased medical technologies from the healthcare industry. Participating firms would have received permanent showrooms and exclusive access to all of the center's resources and amenities.

Construction was scheduled to begin in 2009 with a completion date of 2011, but the World Product Center ultimately withdrew from a tenancy deal with would-be developer Extell Development Company.

 55 ハドソン・ヤードの計画 
When the World Product Center was canceled, the site of 555 West 33rd Street became available for development again. The , 51-story 55 Hudson Yards building was designed to take its place, although the building is an office building rather than a medical building.

The building, at 11th Avenue's east side between 33rd and 34th Streets, is located to the north of 35 Hudson Yards, and on the west side of the Hudson Park and Boulevard, adjacent to 50 Hudson Yards and the entrance to the new 34th Street New York City Subway station. Located on the site of the canceled World Product Center, the building, designed by Eugene Kohn and Kevin Roche, cost . The building is the first collaborative effort between the two firms. In 2013, Extell was paid by The Related Companies in exchange for the 55/One Hudson Yards building, in a deal that allowed Related to develop the site.

Construction was originally not set to start until at least half of the building was pre-leased, but was fast-tracked to 2015. Because of the 7 Subway Extension construction underneath the building, the foundation had already been built; the 55 Hudson Yards building sits over a ventilation building and a station entrance for the extension. Construction started on January 22, 2015, and was expected to be complete by 2019. 55 Hudson Yards was built with a concrete frame, as opposed to a steel frame, in order to speed up construction and lower costs. , construction was up to 38 floors and the tower was to be complete by 2018. The tower topped out in August 2017. Tenants began moving into the building in early 2019.

 Ownership and tenants 

By November 2014, the Japanese real estate investment firm Mitsui Fudosan was looking to buy part of the tower. The move came after J.P. Morgan Chase put forth a proposal to invest in the tower, but later withdrew due to the New York City government's refusal to give J.P. Morgan Chase about in subsidies and tax breaks. On December 30, 2014, Mitsui Fudosan bought a 92.09% stake in the project for $259 million.

As of November 2019, the building was 97.3% leased to 20 tenants:

 Floors 1-2: Mount Sinai Health System
 Floors 3-14: Point72 Asset Management
 Floor 3 subleased to Elite Model Management
 subleased to Light Sky Macro LP
 subleased to Coinbase
 Floors 15-17: MarketAxess
 Floors 18-21: Boies Schiller Flexner LLP
 subleased to Ashurst LLP
 Floor 22: Centiva Capital; Nut Tree Capital Management; Mitsui Fudosan
 Floor 23: Vista Equity Partners
 Floors 24–25: Facebook
 Floors 26-27: Cognizant
 Floor 28: Arosa Capital Management; Healthcor Management
 Floor 29: Engineer's Gate
 Floors 30-39: Milbank LLP
 Floors 40-41: Silver Lake Partners
 Floors 42-46: Cooley LLP
 subleased to Cinctive Capital
 Floor 47: Antara Capital Partners
 Floor 48: Stonepeak Partners
 Floors 49-51: Third Point Management

Related announced in December 2018 that French chef Éric Kayser would operate a fine-casual bakery & cafe entitled Maison Kayser that will also offer catering to the nearby office towers. The Maison Kayser chain filed for bankruptcy in September 2020 and it is unknown whether the cafe will reopen.

 Design changes 

55 Hudson Yards was originally conceived as a , building with 56 stories at 550-570 West 34th Street. It was expected to keep the latticed glass facade and a curved roof, as well as many of the old design plans of the World Product Center because Extell was designing One Hudson Yards. However, in late 2013, a design change was made that downsized the building to . Also, the building would have had a modified beige façade, as well as a flat roof. The building sits on an area bounded by 11th Avenue, Hudson Park and Boulevard, and 33rd and 34th Streets. The lowest ten floors span each while the floors in the stories above each measure .

Early projections placed the building as having either 47 or 50 floors, but final plans amounted to 51 stories. (the top floor is a mechanical floor, with office space occupying the fifty floors below it).

In May 2014, renderings for the building changed for the second time. The building's third plan depicted a facade with a mostly metallic overlay and a base larger than the rest of the building. However, the square footage and height remained the same as in the second plan. The building's facade was based on the cast iron facades of buildings in SoHo.

 Architecture and design 

The building has energy-efficient features, and was certified as LEED Gold by the U.S. Green Building Council on October 30, 2019. Features of the building include destination dispatch elevators; column-less exterior corners featuring floor-to-ceiling windows; and ceilings. To lower costs and allow flexibility during the build, construction emphasized the use of concrete over steel.

The tower includes terraces on the tenth floor and within the tower's interior floors and its base; the tenth-floor terrace overlooks the Hudson Park and Boulevard. The terrace contains an outdoor wooden balcony, as well as for landscaping.