MOMus–Museum of Modern Art–Costakis Collection

MOMus Modern, officially MOMus Museum of Modern Art Costakis Collection, is a modern art museum located in Thessaloniki, Central Macedonia, Greece. Established in 1997, the institution is of major international significance primarily because it houses the Costakis Collection, widely regarded as the second most important collection of Russian avant-garde art in the world, after that of the Tretyakov Gallery in Moscow. The museum operates under the Metropolitan Organisation of Museums of Visual Arts of Thessaloniki, a broader umbrella formed in 2018 to unite several visual arts institutions in the city.

The museum was founded in 1997 on the occasion of Thessaloniki serving as the European Capital of Culture. Its establishment was formalized by a law passed in the Greek Parliament under the direction of the Minister of Culture at the time, Evangelos Venizelos. Initially named the State Museum of Contemporary Art, its development was driven by the Greek state's acquisition of a substantial portion of the Costakis Collection on 31 March 2000 for 14,200,000,000 drachmas. In 2013, a decision was made to merge the institution with the Macedonian Museum of Contemporary Art, and by 2018, it was integrated into the newly formed MOMus organization, adopting its current name. The museum's first director was Miltiadis Papanikolaou, an art history professor at the Aristotle University, who served from 1997 to 2006. He was succeeded by Maria Tsantsanoglou, a specialist in the Russian avant-garde. The museum also organized the first six editions of the Thessaloniki Biennale of Contemporary Art.

The core of the museum's holdings consists of 1,275 works from the Costakis Collection, encompassing paintings, sculptures, drawings, constructions, posters, and icons representing the Russian avant-garde. This collection was instrumental in introducing Western audiences to Russian avant-garde movements through touring exhibitions in cities such as Dusseldorf, New York, Berlin, Paris, and Cologne. Beyond the Russian works, the museum's collections originally included around 200 paintings and sculptures donated by the Cultural Capital 1997 Organization, alongside significant donations from artists. Following the 2018 MOMus restructuring, approximately 300 contemporary artworks were transferred to the management of the Thessaloniki Museum of Contemporary Art. The museum also previously oversaw the Thessaloniki Design Museum, which lacked a permanent exhibition space, and its photography collections were spun off into a separate photography museum.

The permanent exhibition features over a hundred works from the Russian avant-garde, showcasing key figures and movements. Notable artists represented include Kazimir Malevich, Vladimir Tatlin, Wassily Kandinsky, El Lissitzky, and Lyubov Popova. Other significant avant-garde artists in the collection include Olga Rozanova, Nadezhda Udaltsova, Alexander Rodchenko, Solomon Nikritin, Ivan Kliun, Gustav Klutsis, Ilya Chashnik, Aleksandr Drevin, and K. Vialov. Among the notable works by Greek diaspora artists donated to the museum are The Chapel of the Heavenly Stairway by Stylianos Antonakos, Gridlock by Chris Giannakos, and Group of Four Figures by Joannis Avramidis. Sculptures by Avramidis are also displayed on the museum's exterior.

The museum is housed in the renovated building of the former Lazariston Monastery, a Catholic monastery founded in 1861. Located in the Borough of Stavroupoli in west Thessaloniki, approximately two kilometers from the city center, the site falls within the administrative unit of Pavlos Melas. The monastery building was renovated in 1997 to accommodate the museum's collections. However, due to spatial constraints, a medium-term relocation has been considered. The museum also operates a branch, known as MOMus Experimental or the Experimental Center for the Arts, which is housed in Warehouse B1 at Pier A of the Port of Thessaloniki.

The museum is located in the Stavroupoli district of Thessaloniki, Greece. It is accessible to the public and maintains a web presence at greekstatemuseum.com, offering information in Greek, English, and Russian. As part of the MOMus network, it shares operational and administrative frameworks with other visual arts museums in Thessaloniki. The institution's mission includes preserving and displaying contemporary art, advancing public art education, and fostering scientific research into the history and theory of contemporary art, while also supporting art historians specializing in museology.