Two referendums were held in Switzerland on 16 October 1966.[1] Voters were asked whether they approved of an amendment to the constitution on Swiss citizens living abroad and a popular initiative "for the fight against alcoholism".[1] The constitutional amendment was approved whilst the popular initiative was rejected.[1] 
  Results
 Constitutional amendment
   | Choice | Popular vote | Cantons | 
  | Votes | % | Full | Half | Total | 
  | For | 491,220 | 68.1 | 19 | 6 | 22 | 
  | Against | 230,483 | 31.9 | 0 | 0 | 0 | 
  | Blank votes | 33,719 | – | – | – | – | 
  | Invalid votes | 1,163 | – | – | – | – | 
  | Total | 756,585 | 100 | 19 | 6 | 22 | 
  | Registered voters/turnout | 1,580,573 | 47.9 | – | – | – | 
  | Source: Nohlen & Stöver | 
 Popular initiative on alcoholism
   | Choice | Votes | % | 
  | For | 174,242 | 23.4 | 
  | Against | 571,267 | 76.6 | 
  | Blank votes | 12,697 | – | 
  | Invalid votes | 1,164 | – | 
  | Total | 759,370 | 100 | 
  | Registered voters/turnout | 1,580,573 | 48.0 | 
  | Source: Nohlen & Stöver | 
 References
   - ^ a b c Nohlen, D & Stöver, P (2010) Elections in Europe: A data handbook, p1919 ISBN 9783832956097