The siege of Deko Neimoidia occurred in 19 BBY during the period known as the Clone Wars. This conflict took place before the events of the fall of Cato Neimoidia and coincided roughly with the timeline of the Outer Rim Sieges.
As the Clone Wars neared their conclusion, the Galactic Republic successfully dislodged the Trade Federation from their financial strongholds located in the Colonies. This Republic victory forced the Neimoidians to seek refuge in the Outer Rim Territories. One of these purse worlds, Deko Neimoidia, was targeted for invasion by clone troopers belonging to the [22nd Air Combat Wing], who were under the command of Jedi General Roan Shryne. Commander Cody, alongside Jedi Generals Obi-Wan Kenobi and Anakin Skywalker, participated in the assault on the Trade Federation's fortified citadel. The floorplans of this fortress proved invaluable to the Republic forces, giving them an advantage later during their attempt to capture Nute Gunray. Ion Team, a unit of clone commandos, also saw action in this battle. During the conflict, General Shryne earned the respect of Captain Climber, the leader of Ion Team, who would later be responsible for saving Shryne's life.
The fall of Deko Neimoidia, along with the subsequent defeats at Cato and Koru Neimoidia, ultimately led the leaders of the Separatist alliance to establish their new headquarters on the Outer Rim planets of Utapau and Mustafar.