They lost a promotion play-off against Örebro SK in 1999, but five years later, in 2004, Assyriska was promoted to Allsvenskan, the highest league, for the first time as Örebro SK was relegated due to economical problems. Assyriska's debut in Allsvenskan went well in the beginning and they had a couple of notable wins against big clubs as IFK Göteborg with 0–3 and against IF Elfsborg with 1–3. However Assyriska were relegated after only one season in the Allsvenskan, where they finished last. Since then Assyriska had fallen into Division 1 North, but enjoyed a strong season in 2007 to finish champions and were promoted back into the Superettan.