Four referendums were held in Switzerland during 1903.[1] The first was held on 15 March on a federal law on tariffs, and was approved by 59.6% of voters.[1] The second, third and fourth were all held on 25 October concerning an amendment to the federal criminal law, a popular initiative on Swiss residents electing the National Council and an amendment to article 32bis of the constitution.[1] All three were rejected by voters.[1]
The referendums on tariffs and the federal criminal law were optional referendums,[1] which required only a majority of the public vote.[2] The referendum on the changes to National Council elections was popular initiative and the referendum on the constitutional amendment was a mandatory referendum,[1] both of 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]