Provides details of House of Representatives by-elections, from that held for Darling Downs on 14 September 1901 to the most recent held on 5 December 2015 for North Sydney.

Executive summary
This paper provides details of House of Representatives by-elections, from that held for Darling Downs on 14 September 1901 to the most recent held on 5 December 2015 for North Sydney. The following observations can be made about those by-elections:

• there have been 149 by-elections, an average of 3.4 per parliament
• the average number of nominations has grown over the years from 2.2 per by-election to 11.6 per by-election in only four cases was a by-election contested by just a single candidate
• an increasing tendency has been for governments to avoid contesting by-elections in their opponents ’ safe seats
• in only ten cases have the opposition party failed to contest a by-election
• seventy-five of the by-elections followed the resignation of the member, 68 members died in office, there have been five voided elections, and one MP was expelled from the House
• since 1949 most by-elections have been caused by the resignation of the sitting member and have occurred in safe seats
• on 35 occasions the party complexion of a seat has altered at a by-election
• five of the losses have been by the opposition of the day
• the average two-party preferred swing against the government of the day has been 4.0 per cent
• since 1949 the largest two-party swing against a government occurred in Canberra in 1995. The largest swing to a government occurred in McPherson in 1981.