Assembly 1999 was held at Hartwall-Areena in Helsinki, Finland. It was the 8th Assembly party, and the first at this venue. The party system in use was Zepo.

The amiga demo competition was won by Loveboat with their demo Beats, followed by demos from Dual Crew Shining and Mystic. The amiga 64k intro competition was won by Da Jormas followed by Extreme, Spaceballs and Scoopex. The pc demo competition was split into plain dos and 3d accelerated portions, and the dos competition was won by Recreation with Gasoline. Damones and Pyrotech were runners-up. The 3d competition was won by Mature Furk with Virhe, followed by Trauma and Komplex. The pc 64k intro competition was won by Mewlers with Viagra folllowed by Nah Kolor and Reality Benders. The c64 demo competition was won by Panic with Speedway 3 - their third Speedway and their third consecutive win at Assembly! - followed by demos from Scallop and Visac. Pc demoscene veteran Purple Motion (Future Crew) won the mp3 music competition.

Most competitions were put on YouTube;

Animation
Accelerated Demo
Non-Accelerated Demo
Amiga 64K Intro
Tiny Music
MP3 Music
Wild Demo

Results and article appeared in Demojournal #51 (August 1999). A party report appeared in Showtime 14 (March 2000).

Results based on results.txt from scene.org. Some results in the Tiny Music and Animation competitions were double; they were placed twice at several places in the order. The results are presented here as they were in the original file, with the errors.