In the end of the 19th century, Chaidari was a sparsely inhabited rural area. The foundation of the Dromokaiteion Psychiatry prompted the formation of a small settlement in 1887. Fifty-four refugee families from Asia Minor founded the Nea Phokaia settlement in 1924, in between Stratarchou Karaiskaki, N. Plastera, Dodekanisou and I. Venezi Streets. The refugees came from a variety of localities in Asia Minor, and mainly from Phokaia. In 1926 they founded the church of the Dormition and a Primary School, while the Agricultural Refugee Group of New Phokaians promoted the solution of local community problems. Pontic Greeks arrived too and later formed a local Society Club.
The population increase prompted the establishment of the autonomous Chaidari Community, which used to belong to Aigaleo until the 2 April 1935.
P. Lychnaropoulos was the first Community President. Chaidari continued to develop until World War II. The German Occupation of Athens is directly related to Chaidari, since Chaidari hosted the largest concentration camp in Greece, mainly for political opposers and resistance fighters. The rumors on the the torturing and crimes comprised one of the main means of terrorizing the population and preventing resistance. Themos Kornaros, one of the prisoners stresses the importance of the rumors that made Chaidari a synonym to Death and had a greater impact to outsiders than the insiders. The camp occupied 500000 sq. m north of Kavalas Avenue to the foot of the Poikilo (Kaskadan) mountain.
The area today is shared by the municipalities of Peristeri, Chaidari and Petroupoli and hosts military training centres for heavy arms and communications. It is a forrest area.