Senators were elected over a wide range of time throughout 1900 and 1901, and a seat may have been filled months late or remained vacant due to legislative deadlock.

Both the Republicans and the Democrats gained two seats at the expense of various third parties and vacancies.

Special elections were held to fill vacant seats in Pennsylvania, Utah, and Montana (of which the Republicans won the two former and Democrats the latter) as well as to replace appointees in Minnesota, Nebraska, and Vermont (all of which were carried by the Republicans).

[39][40] Republican Matthew Quay was re-elected by the Pennsylvania General Assembly, consisting of the House of Representatives and the Senate, in the 1893 election.

Between January 18 and April 19, 1899, seventy-nine ballots were recorded in an attempt to elect a Senator.

Instead, the legislature adjourned sine die without electing a Senator due to a dispute between Sen. Quay's political machine and an anti-Quay faction within the Republican Party, along with Democratic Party opposition.