Three referendums were held in Switzerland during 1900.^[1] The first was held on 20 May on a federal law on health, accident and military insurance, and was rejected by 69.8% of voters.^[1] The second and third were held on 4 November on introducing proportional representation for National Council elections and the direct election and increase in members of the Federal Council.^[1] Both were rejected by a majority of voters and cantons.^[1]

The referendums on the changes to the National and Federal Councils were popular initiatives,^[1] which required a double majority; a majority of the popular vote and majority of the cantons.^[2] The decision of each canton was based on the vote in that canton.^[2] Full cantons counted as one vote, whilst half cantons counted as half.^[2] The insurance referendum was an optional referendum,^[1] which required only a majority of the public vote.^[2]