Had they voted in favour, the plan was that Sweden would have adopted the euro on 1 January 2006.
(Swedish: Anser du att Sverige skall införa euron som valuta?).
The No vote campaign was led by two organisations, representing left (Folkrörelsen Nej till EU [sv]) and right wing politicians respectively.
While there is government support for membership, all parties have pledged not to join without a referendum in favour of doing so.
[1] A majority of voters in Stockholm voted in favour of adopting the euro (54.7% "yes", 43.2% "no").