The idea for Dekade came when Chrisye thought about previously popular songs that were later forgotten. Believing that all genres of modern music draw inspiration from the past, he spoke with Erwin Gutawa, who agreed that they should make a tribute to the history of Indonesian pop music. They worked together to find songs that they could obtain the rights to use and that matched Chrisye's timbre.

Eventually, they decided on "Kr. Pasar Gambir dan Stambul Anak Jampang" to represent the 1940s, "Di Bawah Sinar Bulan Purnama" to represent the 1950s, "Dara Manisku" to represent the 1960s, "Anggrek Bulan" and "Pengalaman Pertama" to represent the 1970s, "Kisah Kasih di Sekolah" and "Sakura dalam Pelukan" to represent the 1980s, "Kangen" to represent the 1990s, and "Seperti Yang Kau Minta" to represent the 2000s. The songs that were chosen originated from a variety of genres, including kroncong, rock and roll, pop, and dangdut.

Upon Chrisye's request, Musica Studios approached Sophia Latjuba to be his duet partner. According to Chrisye, he chose her for her "unique" voice. Although Sophia Latjuba was surprised to be asked and was under contract to a different label, she accepted.

Chrisye and Sophia Latjuba recorded their vocals in Musica Studios' studio in Jakarta, while the Allan Eaton Orchestra recorded the music in their studio in Melbourne, Australia. Arrangement was done by Erwin Gutawa. Work also took place at Sing-Sing Studio in Melbourne and 301 Studio in Sydney. All told, over fifty people worked on the album.

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Wikipedia