Three referendums were held in Switzerland during 1919.^[1] The first two were held on 4 May on amending the constitution to add article 24ter on shipping, and on a constitutional amendment to impose a war tax.^[1] Both proposals were approved by a majority of voters and cantons.^[1] The third was held on 10 August on temporary amendments to article 73 of the constitution, and was also approved in spite of low turnout.^[1]

All three referendums were mandatory referendums,^[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]