The 1860 Londonderry City by-election was held on 2 April following the 13 March 1860 death of the incumbent, the Liberal Party's Sir Robert Ferguson. Ferguson had held the seat since 1830 and had received significant support from the Catholic segment of the constituency. The Liberal Party's candidate Samuel MacCurdy Greer had counted on this support transferring to him, however the Irish Conservative Party's candidate William McCormick, who employed a significant number of Catholic workers, managed to split the Catholic vote. The Liberal Party's Presbyterian support had also been adversely affected by their defeat to the Tories in Londonderry County in 1857, which led many to withdraw from politics.
The election resulted in a narrow victory for McCormick, with a 19-vote majority. He held the seat until his retirement at the 1865 United Kingdom general election.